https://www.suse.com/documentation/sles-12/stor_admin/data/sec_multipath_best_practice.html#sec_multipath_best_practice_san_timeout
Using Multipath with NetApp Devices
When using multipath for NetApp devices, we recommend the following settings in the /etc/multipath.conf file:
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Set the default values for the following parameters globally for NetApp devices:
max_fds max queue_without_daemon no
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Set the default values for the following parameters for NetApp devices in the hardware table:
dev_loss_tmo infinity fast_io_fail_tmo 5 features "3 queue_if_no_path pg_init_retries 50"
SAN Timeout Settings When the Root Device Is Multipathed
A system with root (/) on a multipath device might stall when all paths have failed and are removed from the system because a dev_loss_tmo timeout is received from the storage subsystem (such as Fibre Channel storage arrays).
If the system device is configured with multiple paths and the multipath no_path_retry setting is active, you should modify the storage subsystem’s dev_loss_tmo setting accordingly to ensure that no devices are removed during an all-paths-down scenario. We strongly recommend that you set the dev_loss_tmo value to be equal to or higher than the no_path_retry setting from multipath.
The recommended setting for the storage subsystem’s dev_los_tmo is
<dev_loss_tmo> = <no_path_retry> * <polling_interval>
where the following definitions apply for the multipath values:
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no_path_retry is the number of retries for multipath I/O until the path is considered to be lost, and queuing of IO is stopped.
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polling_interval is the time in seconds between path checks.
Each of these multipath values should be set from the /etc/multipath.conf configuration file. For information, see Section 16.6, Creating or Modifying the /etc/multipath.conf File.