Re: stripe_cache_size and performance [BUG with =64kb]

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Mon, 25 Jun 2007, Justin Piszcz wrote:

>
>
> On Mon, 25 Jun 2007, Justin Piszcz wrote:
>
>> 
>> 
>> On Mon, 25 Jun 2007, Justin Piszcz wrote:
>> 
>>> 
>>> 
>>> On Mon, 25 Jun 2007, Bill Davidsen wrote:
>>> 
>>>> Justin Piszcz wrote:
>>>>> I have found a 16MB stripe_cache_size results in optimal performance 
>>>>> after testing many many values :)
>>>> 
>>>> We have discussed this before, my experience has been that after 8 x 
>>>> stripe size the performance gains hit diminishing returns, particularly 
>>>> for typical write instead of big aligned blocks, possibly with O_DIRECT. 
>>>> I would suggest that as a target even on a low memory machine.
>>>> 
>>>> Do your tests show similar? I was only able to test three and four drive 
>>>> setups using dedicated drives.
>>>> 
>>>> -- 
>>>> bill davidsen <davidsen@tmr.com>
>>>> CTO TMR Associates, Inc
>>>> Doing interesting things with small computers since 1979
>>>> 
>>>> -
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>>>> 
>>> 
>>> Running test with 10 RAPTOR 150 hard drives, expect it to take awhile 
>>> until I get the results, avg them etc. :)
>>> 
>>> 128k,256k,512k,1024k,2048k,4096k,8192k,16384k
>>> 
>>> Justin.
>>> 
>> 
>> Definitely a kernel bug, I set it to 64kb and it stayed in D-state until I 
>> ran alt-sysrq-b.
>> 
>> Pretty nasty!
>> 
>> Justin.
>> 
>
> Ack, help??
>
> [   64.032895] Starting XFS recovery on filesystem: md3 (logdev: internal)
> [   66.210602] XFS: xlog_recover_process_data: bad clientid
> [   66.210656] XFS: log mount/recovery failed: error 5
> [   66.210709] XFS: log mount failed
>
> After I ran 64kb it killed my RAID!
> -
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>

Yeah, I won't be trying that anymore :P

p34:/r1# find lost+found/|wc
     157     157    3369
p34:/r1# du -sh lost+found/
166G    lost+found/
p34:/r1#