Re: Postgresql on SAN

Josh Berkus wrote:

>Anjan,
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>>Has anyone designed/implemented postgresql server on storage networks?
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>Yes, Zapatec.com runs their stuff this way. Probably others as well.
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>>Are there any design considerations?
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>I don't know. Probably.
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>>Are there any benchmarks for storage products (HBAs, Switches, Storage
>>Arrays)?
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>Not specific to PostgreSQL. I'm sure there are generic benchmarks. Keep
>in mind that PostgreSQL needs lots of 2-way I/O, batch writes, and random
>reads.
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>>Any recommendation on the design, resources, references, keeping PG in
>>mind?
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>See above. Also keep in mind that PostgreSQL's use of I/O should improve
>100% in version 7.5.
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We run PG on a SAN array. We currently have it setup so a single PG
instance runs off of a single LUN, this includes the WAL logs. Apart
from that we have made no other special considerations; we just treat it
as a fast RAID array. We haven't got to the stage where the speed of the
SAN is a problem as load hasn't increased as expected. This will change,
when it does I am sure the performance list will be hearing from us ;-).
Out current limitations, as I see it, are amount of memory and then
processing power. The only problem we have had was a dodgy set of kernel
modules (drivers) for the fibre cards, this was because they were beta
drivers and obviously still had a few bugs. This was solved by reverting
to an older version. Everything has run smoothly since then (uptime is
153 days :-)).

Nick