ZFS Build performance

methos

New Member
Dec 19, 2013
20
0
1
Canton, OH
My server build using LSI 9211-8 controller. I'm not seeing the same performance that others have posted. Should this be better?

4 - SAS WD 600GB
1 - Intel s3700 120GB SSD

pool: ISCSI
state: ONLINE
status: The pool is formatted using a legacy on-disk format. The pool can
still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'. Once this is done, the
pool will no longer be accessible on software that does not support feature
flags.
scan: scrub repaired 0 in 0h27m with 0 errors on Sat Feb 8 19:38:42 2014
config:

NAME STATE READ WRITE CKSUM
ISCSI ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
c5t50000C0F02792D2Ad0 ONLINE 0 0 0
c6t50000C0F02795CE6d0 ONLINE 0 0 0
c7t50000C0F02795142d0 ONLINE 0 0 0
c8t50000C0F02CF836Ad0 ONLINE 0 0 0
logs
c1t1d0 ONLINE 0 0 0




NAME SIZE Bonnie Date(y.m.d) File Seq-Wr-Chr %CPU Seq-Write %CPU Seq-Rewr %CPU Seq-Rd-Chr %CPU Seq-Read %CPU Rnd Seeks %CPU Files Seq-Create Rnd-Create

ISCSI 2.17T start 2014.02.08 64G 157 MB/s 92 259 MB/s 85 71 MB/s 33 112 MB/s 86 172 MB/s 34 746.6/s 26 16 13422/s 12956/s
 

gea

Well-Known Member
Dec 31, 2010
2,489
838
113
DE
With your Raid-Z2 you can expect:

- sequential performance is max n * datadisks
in your case: 2 x datadisks

- IO performance is equal to one disk with raid-z
because you need to reposition all heads for every single read write.


You have a sequentlal read performance of 259 MB/s
that means about 130 MB/s per disk - more or less like expected.

What you can do:
- benchmark single disks (pools from one disk/vdev)
to get base data or detect a slower disk

- use raid-10 that give the same sequential write performance of two disks
but can double read and I/O performance.

- use more disks as sequential performance scale with datadisks
- use more vdevs as I/O performance scale with number of vdevs

- use SSD only pools as they have similar/slightly better sequential values
but are 100x better in I/O. Time is over for expensive 10k/15k SAS disks