mirror_zfs/man/man5
Olaf Faaland db2af93d72 Increase default zfs_multihost_fail_intervals and import_intervals
By default, when multihost is enabled for a pool, the pool is
suspended if (zfs_multihost_fail_intervals*zfs_multihost_interval) ms
pass without a successful MMP write.  This is the recommended
configuration.

The default value for zfs_multihost_fail_intervals has been 5, and the
default value for zfs_multihost_interval has been 1000, so pool
suspension occurred at 5 seconds.

There have been multiple cases where a single misbehaving device in a
pool triggered a SCSI reset, and all I/O paused for 5-6 seconds.  This
in turn caused MMP to suspend the pool.

In the cases observed, the rest of the devices were healthy and the
pool was otherwise correctly performing I/O.  The reset was handled
correctly by ZFS, and by suspending the pool MMP made replacing the
device more difficult as well as forcing the host to be rebooted.

Increase the default value of zfs_multihost_fail_intervals to 10, so
that MMP tolerates up to 10 seconds of failed MMP writes before
suspending the pool.

Increase the default value of zfs_multihost_import_intervals to 20, to
maintain the 2:1 safety factor.  This results in a force import taking
approximately 20 seconds when MMP is enabled, with default values.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@whamcloud.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #7709 
Closes #8495
2019-03-13 09:50:48 -07:00
..
Makefile.am Update build system and packaging 2018-05-29 16:00:33 -07:00
spl-module-parameters.5 Update spl module parameters man5 with missing parameter details 2017-10-27 15:46:34 -07:00
vdev_id.conf.5 Add enclosure_symlinks option to vdev_id 2018-12-14 17:27:49 -08:00
zfs-events.5 Add zpool status -s (slow I/Os) and -p (parseable) 2018-11-08 16:47:24 -08:00
zfs-module-parameters.5 Increase default zfs_multihost_fail_intervals and import_intervals 2019-03-13 09:50:48 -07:00
zpool-features.5 Disable 'zfs remap' command 2019-01-15 15:46:58 -08:00