[CentOS] Adding RAM
Ross Walker
rswwalker at gmail.com
Tue Dec 9 01:33:29 UTC 2008
On Dec 8, 2008, at 6:51 PM, Matt <lm7812 at gmail.com> wrote:
>>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
>>> wkB/s
>>> avgrq-sz avgqu-sz await svctm %util
>>> sda 0.38 176.63 70.32 78.26 813.46 2044.82 406.73
>>> 1022.41
>>> 19.24 0.40 19.17 4.04 60.07
>>> sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
>>> 0.00
>>> 5.28 0.00 23.61 19.33 0.00
>>> sda2 0.38 176.63 70.32 78.26 813.45 2044.82 406.73
>>> 1022.41
>>> 19.24 0.40 19.17 4.04 60.07
>>> dm-0 0.00 0.00 70.71 255.60 813.45 2044.82 406.73
>>> 1022.41 8.76 2.90 8.87 1.84 60.10
>>> dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
>>> 0.00
>>> 8.00 0.00 64.20 11.38 0.00
>>
>> Try setting the scheduler to 'deadline' and see if the queue sizes
>> shrink.
>
> I have googled this and having a bit of trouble figuring how to change
> it under CentOS 4.
>
> http://www.wlug.org.nz/LinuxIoScheduler
>
> Does not seem to work on CentOS 4.
>
>> No raid1? Besides adding redundancy, it can help with read
>> performance. I would probably put the mail on a raid 10 though if I
>> had 4 disks to do so.
>
> I plan on moving to faster disks and RAID 1 down the road. Just has
> not happened yet.
Setting scheduler is global in C4 it can be set as a kernel option
with a scheduler=deadline in grub.
-Ross
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