mirror_zfs/man/man5
Paul Dagnelie eef0f4d84e Keep more metaslabs loaded
With the other metaslab changes loaded onto a system, we can 
significantly reduce the memory usage of each loaded metaslab and 
unload them on demand if there is memory pressure. However, none 
of those changes actually result in us keeping more metaslabs loaded. 
If we don't keep more metaslabs loaded, we will still have to wait 
for demand-loading to finish when no loaded metaslab can satisfy our 
allocation, which can cause ZIL performance issues. In addition,
performance is traditionally measured by IOs per unit time, while 
unloading is currently done on a txg-count basis. Txgs can take a 
widely varying range of times, from tenths of a second to several 
seconds. This can result in confusing, hard to predict behavior.

This change simply adds a time-based component to metaslab unloading. 
A metaslab will remain loaded for one minute and 8 txgs (by default) 
after it was last used, unless it is evicted due to memory pressure.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
External-issue: DLPX-65016
External-issue: DLPX-65047
Closes #9197
2019-08-29 10:20:36 -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 Keep more metaslabs loaded 2019-08-29 10:20:36 -07:00
zpool-features.5 List log_spacemap feature in zpool-features.5 manual 2019-07-31 09:29:01 -07:00