Must-have ZPool Attributes
- create zfs pool with
ashift=12for setting the block size on your disks atime=off- disables the Accessed attribute, can double IOPS;compression=lz4- the best compression algorithm;recordsize=(value). Recommended:- 16K for VM images and databases;
- 1M for collections 5-9MB JPG files and GB+ movies;
- the default 128K is good enough.
sync=disabled- for a huge performance gain;xattr=sa- set the Linux extended attributes, this will stop the file system from writing tiny files and write directly to the inodes;
To turn compression on for the pool:
zfs set compression=lz4 POOLNAME
Check:
$ zpool get ashift tank
NAME PROPERTY VALUE SOURCE
tank ashift 12 local
or
$ zpool get all tank
NAME PROPERTY VALUE SOURCE
tank size 5.45T -
tank capacity 0% -
tank altroot /mnt local
tank health ONLINE -
tank guid 13342146495687011760 -
tank version - default
tank bootfs - default
tank delegation on default
tank autoreplace off default
tank cachefile /data/zfs/zpool.cache local
tank failmode continue local
tank listsnapshots off default
tank autoexpand on local
tank dedupratio 1.00x -
tank free 5.44T -
tank allocated 12.1G -
tank readonly off -
tank ashift 12 local
tank comment - default
tank expandsize - -
tank freeing 0 -
tank fragmentation 0% -
tank leaked 0 -
tank multihost off default
tank checkpoint - -
tank load_guid 10696914392094791930 -
tank autotrim off default
tank feature@async_destroy enabled local
tank feature@empty_bpobj active local
tank feature@lz4_compress active local
tank feature@multi_vdev_crash_dump enabled local
tank feature@spacemap_histogram active local
tank feature@enabled_txg active local
tank feature@hole_birth active local
tank feature@extensible_dataset active local
tank feature@embedded_data active local
tank feature@bookmarks enabled local
tank feature@filesystem_limits enabled local
tank feature@large_blocks enabled local
tank feature@large_dnode enabled local
tank feature@sha512 active local
tank feature@skein enabled local
tank feature@userobj_accounting active local
tank feature@encryption enabled local
tank feature@project_quota active local
tank feature@device_removal enabled local
tank feature@obsolete_counts enabled local
tank feature@zpool_checkpoint enabled local
tank feature@spacemap_v2 active local
tank feature@allocation_classes enabled local
tank feature@resilver_defer enabled local
tank feature@bookmark_v2 enabled local
tank feature@redaction_bookmarks enabled local
tank feature@redacted_datasets enabled local
tank feature@bookmark_written enabled local
tank feature@log_spacemap active local
tank feature@livelist enabled local
tank feature@device_rebuild enabled local
tank feature@zstd_compress enabled local
Or using zdb:
$ sudo zdb -e -C tank
MOS Configuration:
version: 5000
name: 'tank'
state: 0
txg: 856
pool_guid: 13342146495687011760
errata: 0
hostid: 2746588504
hostname: ''
com.delphix:has_per_vdev_zaps
vdev_children: 1
vdev_tree:
type: 'root'
id: 0
guid: 13342146495687011760
create_txg: 4
children[0]:
type: 'mirror'
id: 0
guid: 17654950249616959709
metaslab_array: 69
metaslab_shift: 34
ashift: 12
asize: 5999022833664
is_log: 0
create_txg: 4
com.delphix:vdev_zap_top: 66
children[0]:
type: 'disk'
id: 0
guid: 15524432170139117586
path: '/dev/gptid/92a7ff20-3a98-11ec-b453-37c073549e50'
create_txg: 4
com.delphix:vdev_zap_leaf: 67
children[1]:
type: 'disk'
id: 1
guid: 16235157590705019568
path: '/dev/gptid/92b7fb49-3a98-11ec-b453-37c073549e50'
create_txg: 4
com.delphix:vdev_zap_leaf: 68
features_for_read:
com.delphix:hole_birth
com.delphix:embedded_data
atime details:
$ mount|grep tank
tank on /mnt/tank (zfs, local, noatime, nfsv4acls)
tank/home on /mnt/tank/home (zfs, local, noatime, nfsv4acls)
tank/music on /mnt/tank/music (zfs, local, noatime, nfsv4acls)
tank/movies on /mnt/tank/movies (zfs, local, noatime, nfsv4acls)
tank/iocage on /mnt/tank/iocage (zfs, local, noatime, nfsv4acls)
tank/iocage/download on /mnt/tank/iocage/download (zfs, local, noatime, nfsv4acls)
tank/iocage/images on /mnt/tank/iocage/images (zfs, local, noatime, nfsv4acls)
tank/iocage/jails on /mnt/tank/iocage/jails (zfs, local, noatime, nfsv4acls)
tank/iocage/log on /mnt/tank/iocage/log (zfs, local, noatime, nfsv4acls)
tank/iocage/releases on /mnt/tank/iocage/releases (zfs, local, noatime, nfsv4acls)
tank/iocage/templates on /mnt/tank/iocage/templates (zfs, local, noatime, nfsv4acls)