From: Andrey Nekrasov <andy@spylog.ru>
To: linux-kernel@vger.kernel.org
Subject: sata promise and software raid5...
Date: Wed, 26 May 2004 03:46:57 +0400 [thread overview]
Message-ID: <1236867749.20040526034657@spylog.ru> (raw)
Hello,
controller - Promise SATA 150 TX4, linux 2.6.7-rc1-bk1, HDD Maxtor
250Gb (x4)
Why so slowly reads (and writes) with software raid5?
gnome:~ # hdparm -t /dev/sda2
/dev/sda2:
Timing buffered disk reads: 148 MB in 3.01 seconds = 49.16 MB/sec
gnome:~ # hdparm -t /dev/sdb2
/dev/sdb2:
Timing buffered disk reads: 148 MB in 3.02 seconds = 49.01 MB/sec
gnome:~ # hdparm -t /dev/sdc2
/dev/sdc2:
Timing buffered disk reads: 148 MB in 3.03 seconds = 48.90 MB/sec
gnome:~ # hdparm -t /dev/sdd2
/dev/sdd2:
Timing buffered disk reads: 144 MB in 3.00 seconds = 47.96 MB/sec
gnome:~ #
gnome:~ #
gnome:~ # hdparm -t /dev/md0
/dev/md0:
Timing buffered disk reads: 64 MB in 3.12 seconds = 20.52 MB/sec
gnome:~ #
gnome:~ # cat /etc/raidtab
raiddev /dev/md0
raid-level 5
nr-raid-disks 4
nr-spare-disks 0
persistent-superblock 1
parity-algorithm left-symmetric
chunk-size 1024
device /dev/sda2
raid-disk 0
device /dev/sdb2
raid-disk 1
device /dev/sdc2
raid-disk 2
device /dev/sdd2
raid-disk 3
bye
--
next reply other threads:[~2004-05-25 23:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-25 23:46 Andrey Nekrasov [this message]
2004-05-26 4:21 ` Willy Tarreau
2004-05-26 13:06 ` evan-lkml
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