Re: Raid 10 chunksize

On 3/25/09 9:28 PM, "Mark Kirkwood" <markir(at)paradise(dot)net(dot)nz> wrote:

> I wrote:
>> Scott Marlowe wrote:
>>
>>>
>>> Can you try changing the chunksize on the test box you're testing on
>>> to see if that helps?
>>>
>>>
>>
>> Yes - or I am hoping to anyway (part of posting here was to collect
>> some outside validation for the idea). Thanks for your input!
>>
>
> Rebuilt with 64K chunksize:
>
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 24
> number of transactions per client: 12000
> number of transactions actually processed: 288000/288000
> tps = 866.512162 (including connections establishing)
> tps = 866.651320 (excluding connections establishing)
>
>
> So 64K looks quite a bit better. I'll endeavor to try out 256K next week
> too.

Just go all the way to 1MB, md _really_ likes 1MB chunk sizes for some
reason. Benchmarks right and left on google show this to be optimal. My
tests with md raid 0 over hardware raid 10's ended up with that being
optimal as well.

Greg's notes on aligning partitions to the chunk are key as well.

>
> Mark
>
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