Re: SAN performance

I believe 1/0 or 1+0 is aka RAID-10. CX300 doesn't support 0+1.

So far i am aware of two things, the cache page size is 8KB (can be increased or decreased), and the stripe element size of 128 sectors default.

Thanks,
Anjan

-----Original Message-----
From: Mr Pink [mailto:mr_pink_is_the_only_pro(at)yahoo(dot)com]
Sent: Thu 9/23/2004 11:39 AM
To: Anjan Dave; pgsql-performance(at)postgresql(dot)org
Cc:
Subject: Re: [PERFORM] SAN performance

Hi,

I expect you mean RAID 1/0 or 1+0 since the CX300 didn't support RAID 10 last time I looked.

Whether you are using a SAN or not, you should consider putting the WAL files (pg_xlog folder) on
seperate diskes from the DB. Since the log files are mostly written to, not read from you could
just use RAID 1.

It's a pity pg doesn't have a way to use a cluster of servers to get the most out of your
expensive SAN.

I read a comment earlier about setting block sizes to 8k to math pg's block size. Seems to make
sense, you should check it out.

Have fun,
Mr Pink

--- Anjan Dave <adave(at)vantage(dot)com> wrote:

> Hello,
>
>
>
> I'll be moving a DB from internal RAID-10 SCSI storage to an EMC CX300
> FC RAID-10 LUN, bound to the host. I've setup a test host machine and a
> test LUN. The /var/lib/pgsql/data folder is sym-linked to a partition on
> the LUN.
>
>
>
> Other than the shared_buffers, effective cache size, and sort memory, I
> am not sure if I need to change any other parameters in the
> postgresql.conf file for getting maximum performance from the EMC box.
>
>
>
> Is there a general guideline for setting up postgres database and the
> tunable parameters on a SAN, especially for EMC?
>
>
>
> Appreciate any help,
>
>
>
> Thanks,
> Anjan
>
>

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