iorder to understand what is going in your system you should:
1. determine the access pattern to the volume. meaning:
sequetial ? random access ?
sync io ? async io ?
mostly read ? mostly write ?
Are you using small buffers ? big buffers ?
2. you should test the controller capabilty.
meaning :
see if dd'in for each disk in the system seperately reduces the total
throughput.
On 1/18/07, Sevrin Robstad <quackyo@xxxxxxxx> wrote:
I've tried to increase the cache size - I can't measure any difference.....
Raz Ben-Jehuda(caro) wrote:
> did u increase the stripe cache size ?
>
>
> On 1/18/07, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> wrote:
>> Sevrin Robstad wrote:
>> > I'm suffering from bad performance on my RAID5.
>> >
>> > a "echo check >/sys/block/md0/md/sync_action"
>> >
>> > gives a speed at only about 5000K/sec , and HIGH load average :
>> >
>> > # uptime
>> > 20:03:55 up 8 days, 19:55, 1 user, load average: 11.70, 4.04, 1.52
>> >
>> > kernel is 2.6.18.1.2257.fc5
>> > mdadm is v2.5.5
>> >
>> > the system consist of an athlon XP1,2GHz and two Sil3114 4port S-ATA
>> > PCI cards with a total of 6 250gb S-ATA drives connected.
>> >
>> > [root@compaq ~]# mdadm --detail /dev/md0
>> > /dev/md0:
>> > Version : 00.90.03
>> > Creation Time : Tue Dec 5 00:33:01 2006
>> > Raid Level : raid5
>> > Array Size : 1218931200 (1162.46 GiB 1248.19 GB)
>> > Device Size : 243786240 (232.49 GiB 249.64 GB)
>> > Raid Devices : 6
>> > Total Devices : 6
>> > Preferred Minor : 0
>> > Persistence : Superblock is persistent
>> >
>> > Update Time : Wed Jan 17 23:14:39 2007
>> > State : clean
>> > Active Devices : 6
>> > Working Devices : 6
>> > Failed Devices : 0
>> > Spare Devices : 0
>> >
>> > Layout : left-symmetric
>> > Chunk Size : 256K
>> >
>> > UUID : 27dce477:6f45d11b:77377d08:732fa0e6
>> > Events : 0.58
>> >
>> > Number Major Minor RaidDevice State
>> > 0 8 1 0 active sync /dev/sda1
>> > 1 8 17 1 active sync /dev/sdb1
>> > 2 8 33 2 active sync /dev/sdc1
>> > 3 8 49 3 active sync /dev/sdd1
>> > 4 8 65 4 active sync /dev/sde1
>> > 5 8 81 5 active sync /dev/sdf1
>> > [root@compaq ~]#
>> >
>> >
>> > Sevrin
>> > -
>> > To unsubscribe from this list: send the line "unsubscribe
>> linux-raid" in
>> > the body of a message to majordomo@xxxxxxxxxxxxxxx
>> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>> If they are on the PCI bus, that is about right, you probably should be
>> getting 10-15MB/s, but it is about right. If you had each drive on its
>> own PCI-e controller, then you would get much faster speeds.
>>
>> -
>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>
>
--
Raz
-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
