ZFS nice commands
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Some ZFS commands I use often (on Linux)
zpool
Get zpool status
# zpool status -P
pool: rpool
state: ONLINE
scan: scrub repaired 0B in 0h41m with 0 errors on Tue Nov 27 11:49:30 2018
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
/dev/disk/by-id/ata-SanDisk_SDSSDHII960G_151740411091-part4 ONLINE 0 0 0
- -P : Display real paths for vdevs instead of only the last component of the path.
# zpool status -PL
pool: rpool
state: ONLINE
scan: scrub repaired 0B in 0h41m with 0 errors on Tue Nov 27 11:49:30 2018
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
/dev/sda4 ONLINE 0 0 0
errors: No known data errors
- -P : Display real paths for vdevs instead of only the last component of the path.
- -L : Display real paths for vdevs resolving all symbolic links.
Get zpool size
# zpool list
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
rpool 788G 609G 179G - 53% 77% 1.00x ONLINE -
Ooooh... bad fragmentation! So what? It's a SSD!
Get the ashift value
# zpool list -o name,ashift
NAME ASHIFT
rpool 9
which means 2^9=512 := 512 byte blocks in the backend... that is uncool for SSDs.
# echo $[ 2 ** 12 ]
4096
# zpool set ashift=12 rpool
# zpool list -o name,ashift
NAME ASHIFT
rpool 12
which means 2^12=4096 := 4k blocks in the backend. Perfect!
zfs
zdb
Traverse all blocks
# zdb -b rpool
Traversing all blocks to verify nothing leaked ...
loading space map for vdev 0 of 1, metaslab 196 of 197 ...
609G completed (4928MB/s) estimated time remaining: 0hr 00min 00sec
No leaks (block sum matches space maps exactly)
bp count: 32920989
ganged count: 0
bp logical: 760060348928 avg: 23087
bp physical: 650570102784 avg: 19761 compression: 1.17
bp allocated: 654308115456 avg: 19875 compression: 1.16
bp deduped: 0 ref>1: 0 deduplication: 1.00
SPA allocated: 654308115456 used: 77.33%
additional, non-pointer bps of type 0: 237576
Dittoed blocks on same vdev: 1230844
