Re: raid10 write performance

On 6/22/2010 4:31 AM, Grzegorz Jaśkiewicz wrote:
> Hi folks,
>
> is there a general problem with raid10 performance postgresql on it?
> We see very low performance on writes (2-3x slower than on less
> performant servers). I wonder if it is solely problem of raid10
> configuration, or if it is postgresql's thing.
>

RAID 10 is the commonly suggested layout for DB's as its performance to
redundancy is good.
The question that begs to be ask is what is the IO layout on the other
servers your comparing against.

> Would moving WAL dir to separate disk help potentially ?
>

Yes it can have a big impact.
http://www.westnet.com/~gsmith/content/postgresql/TuningPGWAL.htm
http://wiki.postgresql.org/wiki/Performance_Analysis_Tools

http://wiki.postgresql.org/wiki/Performance_Optimization

> We're running centos 5.4, and server config is:
>
> x3550 M2, xeon 4c e5530 2.4ghz , 6GB of ram
> disks: ibm 300gb 2.5 SAS
>
> raid: serveRAID M5014 SAS/SATA controller
>
> strip size is the default 128k
>
>
> thanks.
>
>

All legitimate Magwerks Corporation quotations are sent in a .PDF file attachment with a unique ID number generated by our proprietary quotation system. Quotations received via any other form of communication will not be honored.

CONFIDENTIALITY NOTICE: This e-mail, including attachments, may contain legally privileged, confidential or other information proprietary to Magwerks Corporation and is intended solely for the use of the individual to whom it addresses. If the reader of this e-mail is not the intended recipient or authorized agent, the reader is hereby notified that any unauthorized viewing, dissemination, distribution or copying of this e-mail is strictly prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and destroy all occurrences of this e-mail immediately.
Thank you.