From: Tommy Apel Hansen <tommyapeldk@gmail.com>
To: linux-raid@vger.kernel.org
Subject: RAID5 performace issue
Date: Thu, 22 Nov 2012 21:53:54 +0100 [thread overview]
Message-ID: <1767331.K4nRMCSJWv@workstation-home> (raw)
Hello list,
I'm experiencing some issus with RAID5 and 5 or more disks, while doign
sequencial 4k writes to and array with 5 or more disks I'm only getting
~279IOPs where when using 4 disks yields ~2752IOPs, it's a 1/10 in IOPs but
with more disks so the result should actually be better the more disks there
is, see results and test below.
Regards
/Tommy
RAID5 5 disks:
echo 16384 > /sys/block/md0/md/stripe_cache_size
mkfs.xfs -l su=32k -d su=512k,sw=4 -f /dev/md0
mdadm -D /dev/md0:
Version : 1.2
Creation Time : Wed Nov 21 20:36:46 2012
Raid Level : raid5
Array Size : 7814051840 (7452.06 GiB 8001.59 GB)
Used Dev Size : 1953512960 (1863.02 GiB 2000.40 GB)
Raid Devices : 5
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Thu Nov 22 20:59:27 2012
State : clean
Active Devices : 5
Working Devices : 5
Failed Devices : 0
Spare Devices : 0
Layout : right-asymmetric
Chunk Size : 512K
fio sequential write ioengine=sync, iodepth=1 :
-- 512b bw=2207.3KB/s, iops=4414
-- 1k bw=3586.4KB/s, iops=3586
-- 2k bw=5584.7KB/s, iops=2792
-- 4k bw=1119.6KB/s, iops=279
-- 8k bw=2107.4KB/s, iops=263
-- 16k bw=4438.3KB/s, iops=277
-- 32k bw=6826.7KB/s, iops=213
-- 64k bw=9167.5KB/s, iops=143
-- 128k bw=16580KB/s, iops=129
fio sequential read ioengine=sync, iodepth=1:
-- 512b bw=14069KB/s, iops=28137
-- 1k bw=20511KB/s, iops=20511
-- 2k bw=25173KB/s, iops=12586
-- 4k bw=30654KB/s, iops=7663
-- 8k bw=47503KB/s, iops=5937
-- 16k bw=59487KB/s, iops=3717
-- 32k bw=72496KB/s, iops=2265
-- 64k bw=80117KB/s, iops=1251
-- 128k bw=88286KB/s, iops=689
RAID5 4 disks:
mkfs.xfs -l su=32k -d su=512k,sw=3 -f /dev/md0
mdadm -D /dev/md0
Version : 1.2
Creation Time : Thu Nov 22 21:29:45 2012
Raid Level : raid5
Array Size : 5860538880 (5589.05 GiB 6001.19 GB)
Used Dev Size : 1953512960 (1863.02 GiB 2000.40 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Thu Nov 22 21:35:28 2012
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : right-asymmetric
Chunk Size : 512K
fio sequential write ioengine=sync, iodepth=1 :
-- 512b bw=2553.2KB/s, iops=5107
-- 1k bw=5486.9KB/s, iops=5486
-- 2k bw=10785KB/s, iops=5392
-- 4k bw=11012KB/s, iops=2752
-- 8k bw=15316KB/s, iops=1914
-- 16k bw=15933KB/s, iops=995
-- 32k bw=17368KB/s, iops=542
-- 64k bw=20633KB/s, iops=322
-- 128k bw=26263KB/s, iops=205
fio sequential read ioengine=sync, iodepth=1:
-- 512b bw=14112KB/s, iops=28224
-- 1k bw=20512KB/s, iops=20512
-- 2k bw=25199KB/s, iops=12599
-- 4k bw=30438KB/s, iops=7609
-- 8k bw=48065KB/s, iops=6008
-- 16k bw=68692KB/s, iops=4293
-- 32k bw=82708KB/s, iops=2584
-- 64k bw=96403KB/s, iops=1506
-- 128k bw=111824KB/s, iops=873
reply other threads:[~2012-11-22 20:53 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1767331.K4nRMCSJWv@workstation-home \
--to=tommyapeldk@gmail.com \
--cc=linux-raid@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.