Re: best use of an EMC SAN

On 11-Jul-07, at 10:05 AM, Gregory Stark wrote:

> "Dave Cramer" <pg@fastcrypt.com> writes:
>
>> Assuming we have 24 73G drives is it better to make one big
>> metalun and carve
>> it up and let the SAN manage the where everything is, or is  it
>> better to
>> specify which spindles are where.
>
> This is quite a controversial question with proponents of both
> strategies.
>
> I would suggest having one RAID-1 array for the WAL and throw the
> rest of the

This is quite unexpected. Since the WAL is primarily all writes,
isn't a RAID 1 the slowest of all for writing ?
> drives at a single big array for the data files. That wastes space
> since the
> WAL isn't big but the benefit is big.
>
> If you have a battery backed cache you might not need even that.
> Just throwing
> them all into a big raid might work just as well.
Any ideas on how to test this before we install the database ?
>
> --
>   Gregory Stark
>   EnterpriseDB          http://www.enterprisedb.com
>