zpool iostat are very low level tools that offer concrete information about the throughput, latency, and some of the usage patterns of individual disks
root@freenas[~]# zpool iostat
capacity operations bandwidth
pool alloc free read write read write
------------ ----- ----- ----- ----- ----- -----
Pool 5.68T 3.38T 50 778 3.67M 12.9M
freenas-boot 1.01G 38.5G 0 0 1.96K 346
------------ ----- ----- ----- ----- ----- -----
Monitoring individual disks
root@freenas[~]# zpool iostat -v
capacity operations bandwidth
pool alloc free read write read write
-------------------------------------- ----- ----- ----- ----- ----- -----
Pool 5.68T 3.38T 50 778 3.69M 12.9M
raidz2 5.68T 3.38T 50 455 3.69M 7.40M
gptid/be57f952-1145-11ea-b476-005056ae2464 - - 18 118 1.20M 3.00M
gptid/c3a79619-1145-11ea-b476-005056ae2464 - - 18 117 1.20M 3.00M
gptid/c8fa5764-1145-11ea-b476-005056ae2464 - - 18 117 1.20M 3.00M
gptid/ce5801c2-1145-11ea-b476-005056ae2464 - - 18 117 1.20M 3.00M
gptid/d3afdfa5-1145-11ea-b476-005056ae2464 - - 18 118 1.20M 3.00M
logs - - - - - -
gptid/d57dfe4d-1145-11ea-b476-005056ae2464 254M 92.8G 0 322 0 5.52M
-------------------------------------- ----- ----- ----- ----- ----- -----
freenas-boot 1.01G 38.5G 0 0 1.96K 346
da0p2 1.01G 38.5G 0 0 1.96K 346
-------------------------------------- ----- ----- ----- ----- ----- -----
root@freenas[~]#
get pool status
root@freenas[~]# zpool status -v Pool
pool: Pool
state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
the pool may no longer be accessible by software that does not support
the features. See zpool-features(7) for details.
scan: scrub in progress since Sat Jun 15 00:00:04 2024
4.69T scanned at 179M/s, 3.85T issued at 146M/s, 5.66T total
0 repaired, 67.96% done, 0 days 03:36:22 to go
config:
NAME STATE READ WRITE CKSUM
Pool ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
gptid/be57f952-1145-11ea-b476-005056ae2464 ONLINE 0 0 0
gptid/c3a79619-1145-11ea-b476-005056ae2464 ONLINE 0 0 0
gptid/c8fa5764-1145-11ea-b476-005056ae2464 ONLINE 0 0 0
gptid/ce5801c2-1145-11ea-b476-005056ae2464 ONLINE 0 0 0
gptid/d3afdfa5-1145-11ea-b476-005056ae2464 ONLINE 0 0 0
logs
gptid/d57dfe4d-1145-11ea-b476-005056ae2464 ONLINE 0 0 0
errors: No known data errors
root@freenas[~]#