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VIRTUAL SCSI

Virtual SCSI is based on a client/server relationship. The Virtual I/O Server owns the physical resources and acts as server or, in SCSI terms, target device. The client logical partitions access the virtual SCSI backing storage devices provided by the Virtual I/O Server as clients.

Virtual SCSI server adapters can be created only in Virtual I/O Server. For HMC-managed systems, virtual SCSI adapters are created and assigned to logical partitions using partition profiles.

The vhost SCSI adapter is the same as a normal SCSI adapter. You can have multiple disks assigned to it. Usually one virtual SCSI server adapter mapped to one virtual SCSI client adapter will be configured, mapping backing devices through to individual LPARs. It is possible to map these virtual SCSI server adapters to multiple LPARs, which is useful for creating virtual optical and/or tape devices, allowing removable media devices to be shared between multiple client partitions.

on VIO server:
root@vios1: / # lsdev -Cc adapter
vhost0  Available       Virtual SCSI Server Adapter
vhost1  Available       Virtual SCSI Server Adapter
vhost2  Available       Virtual SCSI Server Adapter


The client partition accesses its assigned disks through a virtual SCSI client adapter. The virtual SCSI client adapter sees the disks, logical volumes or file-backed storage through this virtual adapter as virtual SCSI disk devices. 

on VIO client:
root@aix21: / # lsdev -Cc adapter
vscsi0 Available  Virtual SCSI Client Adapter

root@aix21: / # lscfg -vpl hdisk2
  hdisk2           U9117.MMA.06B5641-V6-C13-T1-L890000000000  Virtual SCSI Disk Drive

In SCSI terms:
virtual SCSI server adapter: target
virtual SCSI client adapter: initiator
(Analogous to server client model, where client is the initiator.)

Physical disks presented to the Virtual I/O Server can be exported and assigned to a client partition in a number of different ways:
- The entire disk is presented to the client partition.
- The disk is divided into several logical volumes, which can be presented to a single client or multiple different clients.
- With the introduction of Virtual I/O Server 1.5, files can be created on these disks and file-backed storage can be created.
- With the introduction of Virtual I/O Server 2.2 Fixpack 24 Service Pack 1 logical units from a shared storage pool can be created.

The IVM and HMC environments present 2 different interfaces for storage management under different names. Storage Pool interface under IVM is essentially the same as LVM under HMC. (These are used sometimes interchangeably.) So volume group can refer to both volume groups and storage pools, and logical volume can refer to both logical volumes and storage pool backing devices.

Once these virtual SCSI server/client adapter connections have been set up, one or more backing devices (whole disks, logical volumes or files) can be presented using the same virtual SCSI adapter. 

When using Live Partition Mobility storage needs to be assigned to the Virtual I/O Servers on the target server.

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Number of LUNs attached to a VSCSI adapter:

VSCSI adapters have a fixed queue depth that varies depending on how many VSCSI LUNs are configured for the adapter. There are 512 command elements of which 2 are used by the adapter, 3 are reserved for each VSCSI LUN for error recovery and the rest are used for IO requests. Thus, with the default queue_depth of 3 for VSCSI LUNs, that allows for up to 85 LUNs to use an adapter: (512 - 2) / (3 + 3) = 85. 

So if we need higher queue depths for the devices, then the number of LUNs per adapter is reduced. E.G., if we want to use a queue_depth of 25, that allows 510/28= 18 LUNs. We can configure multiple VSCSI adapters to handle many LUNs with high queue depths, each requiring additional memory. One may have more than one VSCSI adapter on a VIOC connected to the same VIOS if you need more bandwidth.

Also, one should set the queue_depth attribute on the VIOC's hdisk to match that of the mapped hdisk's queue_depth on the VIOS.

Note that to change the queue_depth on an hdisk at the VIOS requires that we unmap the disk from the VIOC and remap it back, or a simpler approach is to change the values in the ODM (e.g. # chdev -l hdisk30 -a queue_depth=20 -P) then reboot the VIOS. 

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File Backed Virtual SCSI Devices

Virtual I/O Server (VIOS) version 1.5 introduced file-backed virtual SCSI devices. These virtual SCSI devices serve as disks or optical media devices for clients.  

In the case of file-backed virtual disks, clients are presented with a file from the VIOS that it accesses as a SCSI disk. With file-backed virtual optical devices, you can store, install and back up media on the VIOS, and make it available to clients.

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Check VSCSI adapter mapping on client:

root@bb_lpar: / # echo "cvai" | kdb | grep vscsi                             <--cvai is a kdb subcommand
read vscsi_scsi_ptrs OK, ptr = 0xF1000000C01A83C0
vscsi0     0x000007 0x0000000000 0x0                aix-vios1->vhost2        <--shows which vhost is used on which vio server for this client
vscsi1     0x000007 0x0000000000 0x0                aix-vios1->vhost1
vscsi2     0x000007 0x0000000000 0x0                aix-vios2->vhost2


Checking for a specific vscsi adapter (vscsi0):

root@bb_lpar: /root # echo "cvscsi\ncvai vscsi0"| kdb |grep -E "vhost|part_name"
priv_cap: 0x1  host_capability: 0x0  host_name: vhost2 host_location:
host part_number: 0x1   os_type: 0x3    host part_name: aix-vios1

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Other way to find out VSCSI and VHOST adapter mapping:
If the whole disk is assigned to a VIO client, then PVID can be used to trace back connection between VIO server and VIO client.

1. root@bb_lpar: /root # lspv | grep hdisk0                                  <--check pvid of the disk is question on client
   hdisk0          00080e82a84a5c2a                    rootvg

2. padmin@bb_vios1: /home/padmin # lspv | grep 5c2a                          <--check which disk has this pvid on vio server
   hdiskpower21     00080e82a84a5c2a                     None

3. padmin@bb_vios1: /home/padmin # lsmap -all -field SVSA "Backing Device" VTD "Client Partition ID" Status -fmt ":" | grep hdiskpower21
   vhost13:0x0000000c:hdiskpower21:pid12_vtd0:Available                      <--check vhost adapter of the given disk

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Managing VSCSI devices (server-client mapping)

1. HMC -> VIO Server -> DLPAR -> Virtual Adapter (create vscsi adapter, name the client which can use it, then create the same in profile)
                                (the profile can be updated: configuration -> save current config.)
                                (in case of an optical device, check out any client partition can connect)
2. HMC -> VIO Client -> DLPAR -> Virtual Adapter (create the same adapter as above, the ids should be mapped, do it in the profile as well)
3. cfgdev (VIO server), cfgmgr (client)                        <--it will bring up vhostX on vio server, vscsiX on client
4. create needed disk assignments:
  -using physical disks:
    mkvdev -vdev hdisk34 -vadapter vhost0 -dev vclient_disk    <--for easier identification useful to give a name with the -dev flag
    rmvdev -vdev <backing dev.>                                <--back. dev can be checked with lsmap -all (here vclient_disk)

  -using logical volumes:
    mkvg -vg testvg_vios hdisk34                               <--creating vg for lv
    lsvg                                                       <--listing a vg
    reducevg <vg> <disk>                                       <--deleting a vg

    mklv -lv testlv_client testvg_vios 10G                     <--creating lv what will be mapped to client    
    lsvg -lv <vg>                                              <--lists lvs under a vg
    rmlv <lv>                                                  <--removes an lv

    mkvdev -vdev testlv_client -vadapter vhost0 -dev <any_name>        <--for easier identification useful to give a name with the -dev flag
                                                                       (here backing device is an lv (testlv_client)
    rmvdev -vdev <back. dev.>                                  <--removes an assignment to the client

  -using logical volumes just with storage pool commands:
   (vg=sp, lv=bd)

    mksp <vgname> <disk>                                       <--creating a vg (sp)
    lssp                                                       <--listing stoarge pools (vgs)
    chsp -add -sp <sp> PhysicalVolume                          <--adding a disk to the sp (vg)
    chsp -rm -sp bb_sp hdisk2                                  <--removing hdisk2 from bb_sp (storage pool)

    mkbdsp -bd <lv> -sp <vg> 10G                               <--creates an lv with given size in the sp
    lssp -bd -sp <vg>                                          <--lists lvs in the given vg (sp)
    rmbdsp -bd <lv> -sp <vg>                                   <--removes an lv from the given vg (sp)

    mkvdev..., rmvdev... also applies

  -using file backed storage pool
    first a normal (LV) storage pool should be created with: mkvg or mksp, after that:
    mksp -fb <fb sp name> -sp <vg> -size 20G                   <--creates a file backed storage pool in the given storage pool with given size
                                                               (it wil look like an lv, and a fs will be created automatically as well)
    lssp                                                       <--it will show as FBPOOL
    chsp -add -sp clientData -size 1G                          <--increase the size of the file storage pool (ClientData) by 1G


    mkbdsp -sp fb_testvg -bd fb_bb -vadapter vhost2 10G        <--it will create a file backed device and assigns it to the given vhost
    mkbdsp -sp fb_testvg -bd fb_bb1 -vadapter vhost2 -tn balazs 8G <--it will also specify a virt. target device name (-tn)

    lssp -bd -sp fb_testvg                                     <--lists the lvs (backing devices) of the given sp
    rmbdsp -sp fb_testvg -bd fb_bb1                            <--removes the given lv (bd) from the sp
    rmsp <file sp name>                                        <--remove s the given file storage pool


removing it:
rmdev -dev vhost1 -recursive
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On client partitions, MPIO for virtual SCSI devices currently only support failover mode (which means only one path is active at a time:
root@bb_lpar: / # lsattr -El hdisk0
PCM             PCM/friend/vscsi                 Path Control Module        False
algorithm       fail_over                        Algorithm                  True


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Multipathing with dual VIO config:

on VIO SERVER:
# lsdev -dev <hdisk_name> -attr                                    <--checking disk attributes
# lsdev -dev <fscsi_name> -attr                                    <--checking FC attributes


# chdev -dev fscsi0 -attr fc_err_recov=fast_fail dyntrk=yes-perm   <--reboot is needed for these
      fc_err_recov=fast_fail                                       <--in case of a link event IO will fail immediately
      dyntrk=yes                                                   <--allows the VIO server to tolerate cabling changes in the SAN

# chdev -dev hdisk3 -attr reserve_policy=no_reserve                <--each disk must be set to no_reservr
    reserve_policy=no_reserve                                      <--if this is configured, dual vio server can present a disk to client



on VIO client:
# chdev -l vscsi0 -a vscsi_path_to=30 -a vscsi_err_recov=fast_fail -P    <--path timout checks health of VIOS and detects if VIO Server adapter isn't responding
    vscsi_path_to=30                            <--by default it is disabled (0), each client adapter must be configured, minimum is 30
    vscsi_err_recov=fast_fail                   <--failover will happen immediately rather than delayed


# chdev -l hdisk0 -a queue_depth=20 -P          <--it must match the queue depth value used for the physical disk on the VIO Server
    queue_depth                                 <--it determines how many requests will be queued on the disk


# chdev -l hdisk0 -a hcheck_interval=60 -a hcheck_mode=nonactive -P    <--health check updates automatically paths state
                                                                       (otherwise failed path must be set manually))
    hcheck_interval=60                        <--how often do hcheck, each disk must be configured (hcheck_interval=0 means it is disabled)
    hcheck_mode=nonactive                     <--hcheck is performed on nonactive paths (paths with no active IO)


Never set the hcheck_interval lower than the read/write timeout value of the underlying physical disk on the Virtual I/O Server. Otherwise, an error detected by the Fibre Channel adapter causes new healthcheck requests to be sent before the running requests time out.

The minimum recommended value for the hcheck_interval attribute is 60 for both Virtual I/O and non Virtual I/O configurations.
In the event of adapter or path issues, setting the hcheck_interval too low can cause severe performance degradation or possibly cause I/O hangs. 

It is best not to configure more than 4 to 8 paths per LUN (to avoid too many hchecks IO), and set the hcheck_interval to 60 in the client partition and on the Virtual I/O  Server.


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TESTING PATH PRIORITIES:

By default all the paths are defined with priority 1 meaning that traffic will go through the first path. 
If you want to control the paths 'path priority' has to be updated.
Priority of the VSCSI0 path remains at 1, so it is the primary path.
Priority of the VSCSI1 path will be changed to 2, so it will be lower priority. 


PREPARATION ON CLIENT:
# lsattr -El hdisk1 | grep hcheck
hcheck_cmd      test_unit_rdy                            <--hcheck is configured, so path should come back automatically from failed state
hcheck_interval 60                              
hcheck_mode     nonactive                       


# chpath -l hdisk1 -p vscsi1 -a priority=2               <--I changed priority=2 on vscsi1 (by default both paths are priority=1)

# lspath -AHE -l hdisk1 -p vscsi0
    priority  1     Priority    True

# lspath -AHE -l hdisk1 -p vscsi1
    priority  2     Priority    True

So, configuration looks like this:
VIOS1 -> vscsi0 -> priority 1
VIOS2 -> vscsi1 -> priority 2


TEST 1:

1. ON VIOS2: # lsmap -all                                 <--checking disk mapping on VIOS2
    VTD                   testdisk
    Status                Available
    LUN                   0x8200000000000000
    Backing device        hdiskpower1
    ...

2. ON VIOS2: # rmdev -dev testdisk                        <--removing disk mapping from VIOS2

3. ON CLIENT: # lspath
    Enabled hdisk1 vscsi0
    Failed  hdisk1 vscsi1                                 <--it will show failed path on vscsi2 (this is coming from VIOS2)

4. ON CLIENT: # errpt                                     <--error report will show "PATh HAS FAILED"
    IDENTIFIER TIMESTAMP  T C RESOURCE_NAME  DESCRIPTION
    DE3B8540   0324120813 P H hdisk1         PATH HAS FAILED

5. ON VIOS2: # mkvdev -vdev hdiskpower1 -vadapter vhost0 -dev testdisk    <--configure back disk mapping from VIOS2

6. ON CLIENT: # lspath                                    <--in 30 seconds path will come back automatically
    Enabled hdisk1 vscsi0
    Enabled hdisk1 vscsi1                                 <--because of hcheck, path came back automatically (no manual action was needed)

7. ON CLIENT: # errpt                                     <--error report will show path has been recovered
    IDENTIFIER TIMESTAMP  T C RESOURCE_NAME  DESCRIPTION
    F31FFAC3   0324121213 I H hdisk1         PATH HAS RECOVERED


TEST 2:

I did the same on VIOS1 (rmdev...disk, which has path priority 1 (IO is going there by default) 

ON CLIENT: # lspath
    Failed  hdisk1 vscsi0
    Enabled hdisk1 vscsi1

ON CLIENT: # errpt                                        <--an additional disk operation error will be in errpt
    IDENTIFIER TIMESTAMP  T C RESOURCE_NAME  DESCRIPTION
    DCB47997   0324121513 T H hdisk1         DISK OPERATION ERROR
    DE3B8540   0324121513 P H hdisk1         PATH HAS FAILED

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How to change a VSCSI adapter on client:

# lspath
Enabled hdisk0 vscsi0
Enabled hdisk0 vscsi2                                                  <--we want to change vsci2 to vscsi1

On VIO client:
1. # rmpath -p vscsi2 -d                                               <--remove paths from vscsi2 adapter
2. # rmdev -dl vscsi2                                                  <--remove adapter

On VIO server:
3. # lsmap -all                                                        <--check assignment and vhost device
4. # rmdev -dev vhost0 -recursive                                      <--remove assignment and vhost device

On HMC:
5. Remove deleted adapter from client (from profil too)
6. Remove deleted adapter from VIOS (from profil too)
7. Create new adapter on client (in profil too)                        <--cfgmgr on client
8. Create new adapter on VIOS (in profil too)                          <-cfgdev on VIO server

On VIO server:
9. # mkvdev -vdev hdiskpower0 -vadapter vhost0 -dev rootvg_hdisk0      <--create new assignment

# lspath
Enabled hdisk0 vscsi0
Enabled hdisk0 vscsi1                                                  <--vscsi1 is there (cfgmgr may needed)

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Assigning and moving DVD RAM between LPARS


1. lsdev -type optical                    <--check if VIOS owns optical device (you should see sg. like: cd0 Available SATA DVD-RAM Drive)
2. lsmap -all                             <--to see if cd0 is already mapped and which vhost to use for assignment (lsmap -all | grep cd0)
3. mkvdev -vdev cd0 -vadapter vhost0      <--it will create vtoptX as a virtual target device (check with lsmap -all )

4. cfgmgr (on client lpar)                <--bring up cd0 device on client (before moving cd0 device rmdev device on client  first)

5. rmdev -dev vtopt0 -recursive           <--to move cd0 to another client, remove assignment from vhost0
6. mkvdev -vdev cd0 -vadapter vhost1      <--create new assignment to vhost1

7. cfgmgr (on other client lpar)          <--bring up cd0 device on other client

(Because VIO server adapter is configured with "Any client partition can connect" option, these pairs are not suited for client disks.)

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Shared Ethernet Adapter (SEA)

A SEA can be used to connect a physical Ethernet network to a virtul Ethernet network. The SEA hosted in the Virtual I/O Server acts as a layer-2 bridge between the internal and external network. With Shared Ethernet Adapters on the Virtual I/O Server, virtual Ethernet adapters on client logical partitions can send and receive outside network traffic.

Shared Ethernet Adapter is a Virtual I/O Server component that bridges a physical Ethernet adapter and one or more virtual Ethernet adapters:
-The real adapter can be a physical Ethernet adapter, a Link Aggregation or EtherChannel device, or a Logical Host Ethernet Adapter . The real adapter cannot be another Shared Ethernet Adapter or a VLAN pseudo-device.
-The virtual Ethernet adapter (trunk adpater in the SEA) must be created with the following settings:

Adapter ID: Any ID for the Virtual ethernet adapter
Port Virtual Ethernet: PVID given to this adapter (usually a VLAN ID which is not used at any other adapter to avoid untagging packets)
IEE 802.1q: Additional VLAN IDs can be specified here
Ethernet bridging: This checkbox enables accessing external networks
Priority: For SEA Failover mode, you can specify which SEA should be the primary (here it is the secondary SEA)


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A Shared Ethernet Adapter provides access by connecting the internal VLANs with the VLANs on the external switches. Using this connection, logical partitions without physical adapters can share the IP subnet with stand-alone systems and other external logical partitions. (A virtual Ethernet adapter connected to the SEA must have the Access External Networks check box enabled.)

The Shared Ethernet Adapter forwards outbound packets received from a virtual Ethernet adapter to the external network and forwards inbound packets to the appropriate client logical partition over the virtual Ethernet link to that logical partition.

IF SEA failover has been configured leave SEA without IP addresses. (It makes maintenance of SEA also easier)

Checking SEA on VIO server:
padmin@vios1: / # lsdev -dev ent* | grep Shared
ent8    Available       Shared Ethernet Adapter

padmin@vios1: / # lsdev -dev ent8 -attr | grep adapter
pvid_adapter  ent4     Default virtual adapter to use for non-VLAN-tagged packets         True
real_adapter  ent0     Physical adapter associated with the SEA                           True

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Quality of Service

Quality of Service (QoS) is a Shared Ethernet Adapter feature which infulences bamdwidth. QoS allows the Virtual I/O Server to give a higher priority to some types of packets. Shared Ethernet Adapter on the VIO Server can inspect bridged VLAN-tagged traffic for the VLAN priority field in the VLAN header. The 3-bit VLAN priority field allows each individual packet to be prioritized with a value from 0 to 7 to distinguish more important traffic from less important traffic. More important traffic is sent preferentially and uses more Virtual I/O Server bandwidth than less important traffic.

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PVID:

The SEA directs packets based on the VLAN ID tags. One of the virtual adapters in the SEA must be designated (at creation) as the default PVID adapter (ent1 on the below picture). Ethernet frames without any VLAN ID tags that the SEA receives from the external network are forwarded to this adapter and assigned the default PVID

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SEA and VLAN traffic:

The VLAN tag information is referred to as VLAN ID (VID). Ports on a switch are configured as being members of a VLAN designated by the VID for that port. The default VID for a port is referred to as the Port VID (PVID). The VID can be added to an Ethernet packet either by a VLAN-aware host, or by the switch in the case of VLAN-unaware hosts.

For VLAN-unaware hosts, a port is set up as untagged and the switch will tag all packets entering through that port with the Port VLAN ID (PVID). The switch will also untag all packets exiting that port before delivery to the VLAN unaware host. A port used to connect VLAN-unaware hosts is called an untagged port, and it can be a member of only one VLAN identified by its PVID.

Hosts that are VLAN-aware can insert and remove their own tags and can be members of more than one VLAN. These hosts are typically attached to ports that do not remove the tags before delivering the packets to the host, but will insert the PVID tag when an untagged packet enters the port.

A port will only allow packets that are untagged or tagged with the tag of one of the VLANs that the port belongs to.

Based on the above image, incoming packets from external networks:
- SEA forwards untagged packets to ent1 and these are tagged with the default PVID=1
- SEA forwards packets with VID=1 or VID=10 to adapter ent1 as well
- before LPAR2 recieves packets Hypervisor will remove VLAN tag
- en0 on LPAR1 will receive untagged packets
- en1 on LPAR1 will receive only packets with VID=10

Outgoing packets to external networks:
- packets sent by LPAR2 will be tagged by Hypervisor, with PVID=1
- packets sent by LPAR1 through en1 are tagged with VID=10 by AIX, and en0 packets are tagged with PVID=1 by Hypervisor
- at VIOS: packets tagged with VID=10, are processed with the VLAN tag unmodified.
- at VIOS: packets with VID=1 (PVID of ent1 in SEA) are untagged before ent1 receives them, then bridged to ent0 and sent out.
 (VLAN-unaware destination devices on the external network will be able to receive these packets.)

(The virtual Ethernet adapter ent1 of the SEA also uses VID 10 and will receive the packet from the POWER Hypervisor with the VLAN tag unmodified. The packet will then be sent out through ent0 with the VLAN tag unmodified. So, only VLAN-capable destination devices will be able to receive these. )

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Shared Ethernet Adapter Failover:

In a Shared Ethernet Adapter failover configuration there are two Virtual I/O Servers, each running a Shared Ethernet Adapter. The Shared Ethernet Adapters communicate with each other on a control channel using two virtual Ethernet adapters configured on a separate VLAN. The control channel is used to carry heartbeat packets between the two Shared Ethernet Adapters. When the primary Shared Ethernet Adapter loses connectivity the network traffic is automatically switched to the backup Shared Ethernet Adapter.

The trunk priority for the Virtual Ethernet adapters on VIO Server 1 (which has the Access external network flag set) is set to 1. This means that normally the network traffic will go through VIO Server 1. VIO Server 2 with trunk priority 2 is used as backup in case VIO Server 1 has no connectivity to the external network.

more info: https://www-304.ibm.com/support/docview.wss?uid=isg3T1011040

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Shared Ethernet Adapter failover with Loadsharing

The Virtual I/O Server Version 2.2.1.0, or later, provides a load sharing function to enable to use the bandwidth of the backup Shared Ethernet Adapter (SEA).It makes an effective use of the backup SEA bandwidth.

In this example the packets of VLAN 10 will go through VIOS1 and packets of VLAN 20 will go through VIOS2.

Prerequisites:
- Both of primary and backup Virtual I/O Servers are at Version 2.2.1.0, or later.
- Two or more trunk adapters are configured for the primary and backup SEA pair.
- The virtual local area network (VLAN) definitions of the trunk adapters are identical between the primary and backup SEA pair.

To create or enable the SEA failover with Load Sharing, you have to enable the load sharing mode on the primary SEA first before enabling load sharing mode on the backup SEA. The load sharing algorithm automatically determines which trunk adapters will be activated and will treat network packets for VLANs in the SEA 
pair. You can not specify the active trunk adapters of the SEAs manually in the load sharing mode.

Changing the SEA to Load Sharing mode:
$ chdev -dev ent6 -attr ha_mode=sharing

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To reduce SEA failover time to minimum these can help:

- For all AIX client partitions, set up Dead Gateway Detection (DGD) on the default route:
1. route change default -active_dgd        <--Set up DGD on the default route
2. in etc/rc.tcpip add: route change default -active_dgd to the        <--it makes this change to permanent
3. no -p -o dgd_ping_time=2        <--set pings interval of a gateway by DGD to 2 seconds
       (default is 5s; 2s will allow faster recovery):
- On the network switch, enable PortFast if Spanning Tree is on or disable Spanning Tree.
- On the network switch, set the channel group for your ports to Active if they are currently set to Passive

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Simplified SEA (without control channel):

SEA can implement a new method to discover SEA pair partners using the VLAN ID 4095 in its virtual switch. After partners are identified, a new SEA high availability (HA) protocol is used to communicate between them.

If the followings are met during SEA creation no control channel adapter is necessary:
-VIOS Version 2.2.3
-Hardware Management Console (HMC) 7.7.8
-Firmware Level 780 or higher

---------------------------------------------------

Good overview of SEA sharing mode + VLANs:
entstat -all entX | grep -e "  Priority" -e "Virtual Adapter" -e "  State:" -e "High Availability Mode" -e "  ent"

Good overview of SEA Link status + MAC address:
entstat -all entX | grep -e "(ent" -e "Type:" -e "Address:" -e "Link Status" -e "Link State:" -e "Switch "

---------------------------------------------------

Checking SEA Load sharing distribution:

# entstat -all ent8 | grep -e "  Priority" -e "Virtual Adapter" -e "  State:" -e "High Availability Mode"

ent8:       SEA adapter
ent4, ent5: Trunk virtual ethernet adapters in SEA

VIO1:
State: PRIMARY_SH                    <--shows it is in load sharing mode and it is the primary SEA adapter (if we were in failover mode)
High Availability Mode: Sharing
Priority: 1
...
Virtual Adapter: ent4
  Priority: 1  Active: False
Virtual Adapter: ent5
  Priority: 1  Active: True

VIO2:
State: BACKUP_SH                    <--shows it is in load sharing mode and it is the backup SEA adapter (if we were in failover mode)
High Availability Mode: Sharing
Priority: 2
...
Virtual Adapter: ent4
  Priority: 2  Active: True
Virtual Adapter: ent5
  Priority: 2  Active: False

---------------------------------------------------

SEA and SEA failover creation:

To create a Shared Ethernet Adapter (SEA) you need:
- <PHYS>: a physical adapter as backend
- <VIRT>: a virtual adapter
- <VLAN>: an internal VLAN ID
- default: specifies the default virtual adapter to be used for non-VLAN-tagged packets
- defaultid:  this VLAN ID used for untagged packets (the PVID used for the SEA device)

for SEA failover:
- <CONT>: a second virtual adapter for the control channel 

+ optional settings:
-netaddr: SEA will periodically ping this IP address, so it can detect network failures
-largesend: enable TCP segmentation offload


 # simple SEA
 $ mkvdev -sea <PHYS> -vadapter <VIRT> -default <VIRT> -defaultid <VLAN>

 # Shared Ethernet Adapter Failover:
 $ mkvdev -sea <PHYS> -vadapter <VIRT> -default <VIRT> -defaultid <VLAN> -attr ha_mode=auto ctl_chan=<CONT>

 # Shared Ethernet Adapter Failover without control channel, example:
 $ mkvdev -sea ent14 -vadapter ent8 ent10 ent12 ent13 -default ent8 -defaultid 4000 -attr jumbo_frames=yes ha_mode=auto
 (After creation possible to change to sharing mode, 1st on primary VIO after backup VIO: chdev -dev ent15 -attr ha_mode=sharing

 (with optional settings)
 $ mkvdev -sea ent0 -vadapter ent2 -default ent2 -defaultid 1 -attr ha_mode=auto ctl_chan=ent3 netaddr=9.3.4.1 largesend=1

(Any interface with an IP address on the adapters used when defining the SEA must be detached.)
(When you want to change something on SEA (enable/disable load sharing...), do the change on the primary SEA first, then set it on the backup SEA.)

---------------

adding a virtual adapter later to the SEA:

chdev -dev entx -attr virt_adapters=entY,entZ
(entX: SEA adapter; entY,entZ: virtual adapters - all virt. adapters has to be listed here, not just the new one)

---------------

Changing SEA online (without downtime):

SEA configured on VIO1 with priority 1 and on VIO2 on priority 2 (it is important when changing sharing mode)
SEA configured in load sharing mode, so first I change it to auto, and after to standby on each VIO where I work:

1.chdev -dev entX -attr ha_mode=auto                        <--1st on VIO1 after VIO2 change to auto mode, so both will have auto

2.chdev -dev entX -attr ha_mode=standby                     <--on VIO1: so network will go through on VIO2
3.rmvdev -sea entX                                        <--on VIO1: remove SEA
4.rmvdev -lnagg entY                                      <--on VIO1: remove Etherchannel
5.<<do any change/HW repair>>
6.mkvdev -lnagg ent0 ent1 -attr mode=8023ad...              <--on VIO1: recreate Etherchannel
7.mkvdev -sea ent2 -vadapter ent8 ent9 ... ha_mode=standby  <--on VIO1: recreate SEA
8.chdev -dev entX -attr ha_mode=auto                        <--on VIO1: set back ha_mode to auto, so traffic will go based on priority

do same tasks (from standby) on VIOS2...when finished:
chdev -dev entX -attr ha_mode=sharing                       <--1st on VIO1 after on VIO2


This works as well:
rmdev -l ent15
chdev -l ent15 -a jumbo_frames=yes
mkdev -l ent15

---------------

SEA Failover testing:

On VIOS1 and VIOS2 virtual adapters have been created. At creation time trunk priority has been set:
VIOS1: 1
VIOS2: 2

With command 'mkvdev' SEAs (ent14) have been created on both VIO

1. check settings:

    VIOS1:
    lsattr -El ent14 | grep ha_mode            <--should show: ha_mode=auto
    netstat -v ent14 | grep Active             <--should show: Priority: 1  Active: True

    VIOS2:
    lsattr -El ent14 | grep ha_mode            <--should show: ha_mode=auto
    netstat -v ent14 | grep Active             <--should show: Priority: 2  Active: False

2. perform manual SEA failover:

    VIOS1:
    chdev -l ent14 -a ha_mode=standby

3. check settings:

    VIOS1:
    lsattr -El ent14 | grep ha_mode            <--should show: ha_mode=standby
    netstat -v ent14 | grep Active             <--should show: Priority: 1  Active: False
    errpt | head                               <--should show: BECOME BACKUP

    VIOS2:
    lsattr -El ent14 | grep ha_mode            <--should show: ha_mode=auto
    netstat -v ent14 | grep Active             <--should show: Priority: 2  Active: True
    errpt | head                               <--should show: BECOME PRIMARY

4. switching back:

    VIOS1:
    chdev -l ent14 -a ha_mode=auto

5. check settings:

    VIOS1:
    lsattr -El ent14 | grep ha_mode            <--should show: ha_mode=auto
    netstat -v ent14 | grep Active             <--should show: Priority: 1  Active: True
    errpt | head                               <--should show: BECOME PRIMARY

    VIOS2:
    lsattr -El ent14 | grep ha_mode            <--should show: ha_mode=auto
    netstat -v ent14 | grep Active             <--should show: Priority: 2  Active: False
    errpt | head                               <--should show: BECOME BACKUP

---------------

thread attribute:

Threading ensures that CPU resources are shared fairly when a Virtual I/O Server provides a mix of SEA and VSCSI services. 
If it set to 1, it will equalize  the priority between virtual disk and SEA network I/O. This throttles Ethernet traffic to prevent it from consuming a higher percentage of CPU resources versus the virtual SCSI activity. This is a concern only when CPU resources are constrained resources.)

padmin@vios1 : /home/padmin # lsdev -dev ent14 -attr | grep thread
thread        1          Thread mode enabled (1) or disabled (0)                            True

Threading is enabled by default for shared Ethernet adapters.
Disable threading when a Virtual I/O Server is not used for VSCSI (chdev –dev entX –attr thread=0).

---------------

entstat -all ent4                                          shows if this adapter is active or not (entstat -all ent4 | grep Active)
netstat -cdlistats | grep -Ei "\(ent|media|link status"    this lists links on all physical adapter (good!!!)

---------------

Configuring the interface on SEA (adding ip...):

cfgassist or mktcpip command:
mktcpip -hostname VIO_Server1 -inetaddr 9.3.5.196 -interface en3 -netmask 255.255.254.0 -gateway 9.3.4.1

---------------

SEA load sharing mode error:

$ chdev -dev ent23 -attr ha _mode=sharing

Method error (/usr/lib/methods/chgsea):
        0514-018 The values specified for the following attributes 
                 are not valid:
ha_mode. Insufficient no. of adapters.


This indicates that you have only 1 virtual adapter configured in the SEA, so load cannot be shared (that is why you cannot chage ha_mode attribute). Add additional Virtual Ethernet Adpater to the SEA for this sharing mode to activate.

---------------

Total Etherchannel failure and LIMBO state on SEA:

During dual VIOS install, when second SEA configured on VIOS2, network connection was lost and received this:

errpt:
CE9566DF   0719154713 P H ent9           TOTAL ETHERCHANNEL FAILURE

entstat for SEA:
    State: LIMBO
    High Availability Mode: Auto
    Priority: 1
...
Virtual Adapter: ent5
  Priority: 1  Active: False
Virtual Adapter: ent4
  Priority: 1  Active: False
Virtual Adapter: ent3
  Priority: 1  Active: False
Virtual Adapter: ent2
  Priority: 1  Active: False


Limbo state means:
The physical network is not operational or network state is unknown, or the Shared Ethernet Adapter cannot ping the specified remote host.

Limbo packets are sent by the primary Shared Ethernet Adapter when it detects that its physical network is not operational, or when it cannot ping the specified remote host (to inform the backup that it needs to become active).

After checking control channel on both SEA, found configuration problem. One of the control channel was in virtual switch ETHERNET0 the other on was in ETHERNET1, so control channel could not work properly. (You can check it in VIOS LPAR properties on HMC, or with entstat command.)

On the VIOS LPAR with wrong control channel:
1. remove SEA device: rmdev...
2. shutdown LPAR and change profile on HMC: control channel virt. adapter to the correct virtual switch
3. start LPAR and create SEA device again.

After this everything was OK.

---------------

NPIV (Virtual Fibre Channel Adapter)

With NPIV, you can configure the managed system so that multiple logical partitions can access independent physical storage through the same physical fibre channel adapter. (NPIV means N_Port ID Virtualization. N_Port ID is a storage term, for node port ID, to identify ports on the nod (FC Adpater) in the SAN area.)
To access physical storage in a typical storage area network (SAN) that uses fibre channel, the physical storage is mapped to logical units (LUNs) and the LUNs are mapped to the ports of physical fibre channel adapters. Each physical port on each physical fibre channel adapter is identified using one worldwide port name (WWPN).

NPIV is a standard technology for fibre channel networks that enables you to connect multiple logical partitions to one physical port of a physical fibre channel adapter. Each logical partition is identified by a unique WWPN, which means that you can connect each logical partition to independent physical storage on a SAN.

To enable NPIV on the managed system, you must create a Virtual I/O Server logical partition (version 2.1, or later) that provides virtual resources to client logical partitions. You assign the physical fibre channel adapters (that support NPIV) to the Virtual I/O Server logical partition. Then, you connect virtual fibre channel adapters on the client logical partitions to virtual fibre channel adapters on the Virtual I/O Server logical partition. A virtual fibre channel adapter is a virtual adapter that provides client logical partitions with a fibre channel connection to a storage area network through the Virtual I/O Server logical partition. The Virtual I/O Server logical partition provides the connection between the virtual fibre channel adapters on the Virtual I/O Server logical partition and the physical fibre channel adapters on the managed system.

The following figure shows a managed system configured to use NPIV:

on VIO server:
root@vios1: / # lsdev -Cc adapter
fcs0      Available 01-00 8Gb PCI Express Dual Port FC Adapter (df1000f114108a03)
fcs1      Available 01-01 8Gb PCI Express Dual Port FC Adapter (df1000f114108a03)
vfchost0  Available       Virtual FC Server Adapter
vfchost1  Available       Virtual FC Server Adapter
vfchost2  Available       Virtual FC Server Adapter
vfchost3  Available       Virtual FC Server Adapter
vfchost4  Available       Virtual FC Server Adapter

on VIO client:
root@aix21: /root # lsdev -Cc adapter
fcs0 Available C6-T1 Virtual Fibre Channel Client Adapter
fcs1 Available C7-T1 Virtual Fibre Channel Client Adapter

Two unique WWPNs (world-wide port names) starting with the letter "c" are generated by the HMC for the VFC client adapter. The pair is critical and both must be zoned if Live Partition Migration is planned to be used. The virtual I/O client partition uses one WWPN to log into the SAN at any given time. The other WWPN is used when the client logical partition is moved to another managed system using PowerVM Live Partition Mobility. 

lscfg -vpl fcsX will show only the first WWPN
fcstat fcsX will show only the active WWPN

Both of them are showing only 1 WWPN but fcstat will show always the active WWPN which is in use (which will change after an LPM), however lscfg will show as a static value the 1st WWPN assigned to the HBA only.

One VFC client adapter per physical port per client partition and maximum 64 active VFC client adapter per physical port. There is always one-to-one relationship between the virtual Fibre Channel client adapter and the virtual Fibre Channel server adapter.

The difference between traditional redundancy with SCSI adapters and the NPIV technology using virtual Fibre Channel adapters is that the redundancy occurs on the client, because only the client recognizes the disk. The Virtual I/O Server is essentially just a pass-through managing the data transfer through the POWER hypervisor. When using Live Partition Mobility storage moves to the target server without requiring a reassignment (opposite with virtual scsi), because the virtual Fibre Channels have their own WWPNs that move with the client partitions on the target server.

After creating an FC client adapter, and trying to make it persistent across restarts, another different pair of virtual WWPNs would be generated, when creating the adapter in the profile. To prevent this undesired situation, which would require another SAN zoning and storage configuration, make sure to save any virtual Fibre Channel client adapter DLPAR changes into a new partition profile by selecting: Configuration -> Save Current Configuration and change the default partition profile to the new profile.

-----------------------------------------------------

NPIV clients num_cmd_elem attribute should not exceed the VIOS adapter’s num_cmd_elems.
If you increase num_cmd_elems on the virtual FC (vFC) adapter, then you should also increase the setting on the real FC adapter. 

-----------------------------------------------------


Check NPIV adapter mapping on client:

root@bb_lpar: / # echo "vfcs" | kdb                                         <--vfcs is a kdb subcommand
...
NAME      ADDRESS             STATE   HOST      HOST_ADAP  OPENED NUM_ACTIVE
fcs0      0xF1000A000033A000  0x0008  aix-vios1 vfchost8  0x01    0x0000    <--shows which vfchost is used on vio server for this client
fcs1      0xF1000A0000338000  0x0008  aix-vios2 vfchost6  0x01    0x0000

-----------------------------------------------------

NPIV creation and how they are related together:

FCS0: Physical FC Adapter installed on the VIOS
VFCHOST0: Virtual FC (Server) Adapter on VIOS
FCS0 (on client): Virtual FC adapter on VIO client

Creating NPIV adapters:
0. install physical FC Adapters to VIO Servrs
1. HMC -> VIO Server -> DLPAR -> Virtual Adapter (don't forget profile (save current))
2. HMC -> VIO Client -> DLPAR -> Virtual Adapter (the ids should be mapped, don't forget profile)
3. cfgdev (VIO server), cfgmgr (client)    <--it will bring up the new adapter vfchostX on vio server, fcsX on client
4. check status:
    lsdev -dev vfchost*                    <--lists virtual FC server adapters
    lsmap -vadapter vfchost0 -npiv         <--gives more detail about the specified virtual FC server adapter
    lsdev -dev fcs*                        <--lists physical FC server adapters
    lsnports                               <--checks NPIV readiness (fabric=1 means npiv ready)
5. vfcmap -vadapter vfchost0 -fcp fcs0      <--mapping the virtual FC adapter to the VIO's physical FC
6. lsmap -all -npiv                        <--checks the maping
7. HMC -> VIO Client -> get the WWN of the adapter    <--if no LPM will be used only the first WWN is needed
8. SAN zoning

-----------------------------------------------------

Checking if VIOS FC Adapter supports NPIV:

On VIOS as padmin:
$ lsnports
name             physloc                        fabric tports aports swwpns  awwpns
fcs0             U78C0.001.DAJX633-P2-C2-T1        1     64     64   2048    2032
fcs1             U78C0.001.DAJX633-P2-C2-T2        1     64     64   2048    2032
fcs2             U78C0.001.DAJX634-P2-C2-T1        1     64     64   2048    2032
fcs3             U78C0.001.DAJX634-P2-C2-T2        1     64     64   2048    2032

value in column fabric:
1 - adapter and the SAN switch is NPIV ready
2 - adapter or SAN switch is not NPIV ready and SAN switch configuration should be checked

-----------------------------------------------------

Getting WWPNs from HMC CLI:

lshwres -r virtualio --rsubtype fc --level lpar -m <Man. Sys.> -F lpar_name,wwpns --header --filter lpar_names=<lpar name>

lpar_name,wwpns
bb_lpar,"c05076066e590016,c05076066e590017"
bb_lpar,"c05076066e590014,c05076066e590015"
bb_lpar,"c05076066e590012,c05076066e590013"
bb_lpar,"c05076066e590010,c05076066e590011"

-----------------------------------------------------

Replacement of a physical FC adapter with NPIV

1. identify the adapter

$ lsdev -dev fcs4 -child
name             status      description
fcnet4           Defined     Fibre Channel Network Protocol Device
fscsi4           Available   FC SCSI I/O Controller Protocol Device

2. unconfigure the mappings

$ rmdev -dev vfchost0 -ucfg
vfchost0 Defined

3. FC adapters and their child devices must be unconfigured or deleted

$ rmdev -dev fcs4 -recursive -ucfg
fscsi4 Defined
fcnet4 Defined
fcs4 Defined

4. diagmenu
DIAGNOSTIC OPERATING INSTRUCTIONS -> Task Selection -> Hot Plug Task -> PCI Hot Plug Manager -> Replace/Remove a PCI Hot Plug Adapter.

-----------------------------------------------------

Changing WWPN number:
There are 2 methods: changing dynamically (chhwres) or changing in the profile (chsyscfg). Both of them are similar and both of them done in HMC CLI.

I. Changing dynamically:

1. get current adapter config:
# lshwres -r virtualio --rsubtype fc -m <man. sys.> --level lpar | grep <LPAR name>
lpar_name=aix_lpar_01,lpar_id=14,slot_num=8,adapter_type=client,state=1,is_required=0,remote_lpar_id=1,remote_lpar_name=aix_vios1,remote_slot_num=123,"wwpns=c0507603a42102d8,c0507603a42102d9"

2. remove adapter from client LPAR: rmdev -Rdl fcsX (if needed unmanage device prior from storage driver)

3. remove adapter dynamically from HMC (it can be done in GUI)

4. create new adapter with new WWPNS dynamically:
# chhwres -r virtualio -m  -o a -p aix_lpar_01 --rsubtype fc -a "adapter_type=client,remote_lpar_name=aix_vios1,remote_slot_num=123,\"wwpns=c0507603a42102de,c0507603a42102df\"" -s 8

5. cfgmgr on client LPAR will bring up adapter with new WWPNs.

6. save actual config to profile (so next profile activation wil not bring back old WWPNs)

(vfc mapping removal did not needed in this case, if there are some problems try reconfig. that one as well at VIOS side)

-----------------------------------------------------

II. changing in the profile:

same as above just some commands are different:

get current config:
# lssyscfg -r prof -m <man. sys.> --filter lpar_names=aix_vios1
aix_lpar01: default:"""6/client/1/aix_vios1/5/c0507604ac560004,c0507604ac560005/1"",""7/client/1/aix_vios1/4/c0507604ac560018,c0507604ac560019/1"",""8/client2/aix_vios2/5/c0507604ac56001a,c0507604ac56001b/1"",""9/client/2/aix_vios2/4/c0507604ac56001c,c0507604ac56001d/1"""

create new adapters in the profile:
chsyscfg -m <man. sys.> -r prof  -i 'name=default,lpar_id=5,"virtual_fc_adapters+=""7/client/1/aix-vios1/4/c0507604ac560006,c0507604ac560007/1"""'

-m             - managed system
-r prof        - profile will be changed
-i '           - attributes
name=default   - name of the profile, which will be changed
lpar_id=5      - id of the client LPAR
7              - adapter id on client (slot id)
client         - adapter type
1              - remote PLAR id (VIOS server LPAR id)
aix_vios1      - remote LPAR name (VIOS server name)
4              - remote slote number (adapter id on VIOS server)
WWPN           - both WWPN numbers (separated  with , )
1              - required or desired (1- required, 0- desired)


Here VFC unmapping was needed:
vfcmap -vadapter vfchost4 -fcp        <--remove mapping
vfcmap -vadapter vfchost4 -fcp fcs2        <--create new mapping

-----------------------------------------------------

Virtual FC login to SAN:

When new LPAR with VFC has been created, before to see LUNs (to install AIX), for the first time VFC Adapter has to be logged in to SAN.
This can be done on HMC (above HMC V7 R7.3) with command chnportlogin

chnportlogin: it allows to allocate, log in and zone WWPNs before the client partition is activated.

On HMC:
1. lsnportlogin -m <man. sys> --filter lpar_ids=4                     <-- list status of VFC adapters (lpar_id should be given)

lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=2,wwpn=c0507607d1150008,wwpn_status=0,logged_in=none,wwpn_status_reason=null
lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=2,wwpn=c0507607d1150009,wwpn_status=0,logged_in=none,wwpn_status_reason=null
lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=3,wwpn=c0507607d115000a,wwpn_status=0,logged_in=none,wwpn_status_reason=null
lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=3,wwpn=c0507607d115000b,wwpn_status=0,logged_in=none,wwpn_status_reason=null

The WWPN status.  Possible values are:
   0 - WWPN is not activated
   1 - WWPN is activated
   2 - WWPN status is unknown


2. chnportlogin -m <man. sys> --id 4 -o login                           <-- activate WWPNs (VFC logs in to SAN)

3. lsnportlogin -m <man. sys> --filter lpar_ids=4                       <-- list status (it should be wwpn_status=1)

lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=2,wwpn=c0507607d1150008,wwpn_status=1,logged_in=vios,wwpn_status_reason=null
lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=2,wwpn=c0507607d1150009,wwpn_status=1,logged_in=vios,wwpn_status_reason=null
lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=3,wwpn=c0507607d115000a,wwpn_status=1,logged_in=vios,wwpn_status_reason=null
lpar_name=bb_lpar,lpar_id=4,profile_name=default,slot_num=3,wwpn=c0507607d115000b,wwpn_status=1,logged_in=vios,wwpn_status_reason=null


4. Storage team can do LUN assginment, after they finished, you can do logout:
   chnportlogin -m <man. sys> --id 4 -o logout

-----------------------------------------------------

IOINFO


If HMC is below V7 R7.3 ioinfo can be used to cause VFC adapters to login to SAN.
ioinfo also can be used for debug purposes or to check if disk are available/which disk is boot disk

It can be reached from SMS menu with number: 8 (Open Firmware Prompt)


IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM
IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM
IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM

          1 = SMS Menu                          5 = Default Boot List
          8 = Open Firmware Prompt              6 = Stored Boot List


     Memory      Keyboard     Network     SCSI     Speaker  ok

0 > ioinfo

!!! IOINFO: FOR IBM INTERNAL USE ONLY !!!
This tool gives you information about SCSI,IDE,SATA,SAS,and USB devices attached to the system

Select a tool from the following

 1. SCSIINFO
 2. IDEINFO
 3. SATAINFO
 4. SASINFO
 5. USBINFO
 6. FCINFO
 7. VSCSIINFO

q - quit/exit

==> 6


Then choose VFC client device from list --> List Attached FC Devices (this will cause that VFC device to login to SAN)
After that on VIOS: lsmap -npiv ... will show LOGGED_IN

(to quit from "ioinfo" command "reset-all" will do a reboot of the LPAR)


-----------------------------------------------------

$ extendvg –f rootvg hdisk1
$ mirrorios hdisk1

SR-IOV - vNIC

SR-IOV

SR-IOV (Single Root IO Virtualization) is a network virtualization technology. The basic idea is, that a physical device can have multiple virtual instances of itself, and these can be assigned to any LPARs running on the managed system. We have only 1 physical adapter, but each LPAR will think it has its own dedicated adapter. This is achieved by creating logical ports above the physical ports on the adapter. These ports will be exist in the Hypervisor (Firmware), so no VIOS is necessary. In order to see new SR-IOV menu points in HMC GUI, Firmware and HMC should be in a correct level.

Dedicated Mode - Shared Mode:
An SR-IOV capable adapter is either in dedicated mode or shared mode.
In dedicated mode, the adapter is owned by one LPAR. Physical ports of the adapter are owned by that partition. (Usual old config.)
In shared mode, adapter is owned by the Hypervisor. In this mode logical ports can be created and these can be assigned to any LPAR.

Logical Port (LP) - Virtual Function (VF)
A Virtual Function (VF) is a general term used by PCI standards.  On IBM Power Systems, SR-IOV implements VFs as logical ports. Each logical port is associated with a physical port of the adapter. (Basically LPs and VFs are the same. In general documentations the term VF is used many times, but during SR-IOV configuration on HMC, I met only LP, so I`ll use LP here. In these standards another term, the Physical Function (PF) also exists, which is the Physical Port.)

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Capacity (SR-IOV desired bandwidth)

During Logical Port (Virtual Function) creation the desired capacity need to be configured. This is similar to the Entitled Capacity (CPU) setting, just here % is used. The configured value is the desired minimum bandwidth in percentage. It is not capped, which means, if there is additional bandwidth that is not being used currently, it will be shared equally among all logical ports. Assignments are made in increments of 2 %  and total assignments for a single port can not exceed 100%. Capacity cannot be changed dynamically. (It is possible to change in profile and after profile activation is needed.)

So, if an LPAR needs, it will have % desired outgoing bandwidth. If additional outgoing bandwidth is available, any partition can use it. If a partition doesn’t need its minimum, that bandwidth is available to other partitions until the owning partition needs it. Capacity settings don’t have any influence on the incoming bandwidth.

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SR-IOV and LPM:

From a virtualization perspective, SR-VIO logical ports are seen as physical adapters at OS level, therefore operations like Live Partition Mobility are not supported when an SR-IOV logical port is configured on the partition (LPAR B).

If a Logical Port is part of a SEA (which bridge traffic from client partitions to the physical network) then client LPAR has only a Virtual Ethernet Adapter (LPAR A), so it can continue using Live Partition Mobility.

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SR-IOV and Link Aggregation

In an LACP configuration multiple primary SR-IOV logical ports are allowed. When LACP (IEEE802.3ad,) configured with multiple main logical ports, only SR-IOV logical ports can be part of the link aggregation and only 1 single logical port can be configured per physical port.

So, with LACP only one logical port per physical port can be used.
(The second configuration, with more than one logical port assigned to a physical port, will not work.)

To prevent users from adding a logical port to the physical port when LACP being used, you can set the logical port capacity to 100%.

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SR-IOV and Etherchannel (NIB):

In an active-passive configuration (Network Interface Backup), SR-IOV logical port can be primary (active) or backup (passive), or both. If more than one primary adapter is configured in an Etherchannel, then SR-IOV logical port cannot be a primary adapter. When an SR-IOV logical port is configured in an active-passive configuration, it must be configured to detect when to fail over from primary to the backup adapter. This can be achieved by configuring an IP address to ping.

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SR-IOV Configuration:
(Here HMC classical GUI has been used, not enhanced HMC GUI.)


1. verify preprequisites: HMC level, Firmware level, compatible SR-IOV adapter, Man. Sys. capabilities (SR-IOV capable: True)

2. change adapter from Dedicated to Shared mode: Man. Sys. Properties --> IO tab --> choose adapter --> click on shared mode

(This happens at Man. Sys. level, so adapter should not be assigned to any LPARs. If you check again after modification, you will see adapter will be owned by Hypervisor. It is possible to switch back to dedicated mode, just already configured logical ports must be de-configured prior to that.)

3. Physical port config: Man. System --> Properties --> IO --> choose an SR-IOV adapter --> choose a port
Here you can configure speed (10Gb), MTU size, label...

4.Logical Port config: Logical Port is mapped to an LPAR so an LPAR has to be chosen before config. It can be done as a DLPAR operation, or it can be done in LPAR profile.

Add a logical port to a Physical Port:
DLPAR: choose LPAR --> Dynamic part. --> SR-IOV Log. Ports --> Action --> Add Log. Port --> choose a phys. port to conf. additional Log. Port.
PROFILE: In LPAR profile, SR-IOV Log. Ports -->  SR-IOV Menu --> Add Log. Port -->  choose a physical port to configure additional Log. Port

After new window will pop up:

Capacity:     Set desired percentage of Log. Port
Promiscuous:  if the logical port will be assigned to a VIOS in a SEA, then enabling promiscuous mode is required.
              (Promiscuous mode can be enabled on only one logical port per physical port.)
              When promiscuous mode is enabled, Allow All VLAN IDs and  Allow all O/S Defined MAC Addresses are the only options available.

After finishing it, on OS level a new adapter will be configured with VF in the name (cfgmgr may needed)

# lsdev -Cc adapter
ent0    Available 02-00 4-Port Gigabit Ethernet PCI-Express Adapter (e414571614102004)
ent1    Available 02-01 4-Port Gigabit Ethernet PCI-Express Adapter (e414571614102004)
ent2    Available 02-02 4-Port Gigabit Ethernet PCI-Express Adapter (e414571614102004)
ent3    Available 02-03 4-Port Gigabit Ethernet PCI-Express Adapter (e414571614102004)
ent4    Available 0C-00 PCIe3 4-Port 10GbE SR Adapter VF(df1028e21410e304)

# entstat -d ent4
...
...
VF Minimum Bandwidth: 24%
VF Maximum Bandwidth: 100%

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vNIC

vNIC (Virtual Network Interface Controller) is a new type of network adapter on AIX 7.1 TL4 (or later) or on AIX 7.2. vNIC adapters are based on SR-IOV technology and with those LPM is possible.

# lsdev -Cc adapter
ent0   Available   Virtual I/O Ethernet Adapter (l-lan)
ent1   Available   Virtual I/O Ethernet Adapter (l-lan)
ent2   Available   Virtual I/O Ethernet Adapter (l-lan)
ent3   Available   Virtual NIC Client Adapter (vnic)
ent4   Available   Virtual NIC Client Adapter (vnic)