Re: Scaling further up

For the disks part - I am looking at a SAN implementation, and I will be
planning a separate RAID group for the WALs.

The controller is a PERC, with 128MB cache, and I think it is writeback.

Other than the disks, I am curious what other people are using in terms
of the horsepower needed. The Quad server has been keeping up, but we
are expecting quite high loads in the near future, and I am not sure if
just by having the disks on a high-end storage will do it.

Thanks,
Anjan

-----Original Message-----
From: Magnus Hagander [mailto:mha(at)sollentuna(dot)net]
Sent: Monday, March 01, 2004 3:54 PM
To: Anjan Dave; pgsql-performance(at)postgresql(dot)org
Subject: RE: [PERFORM] Scaling further up

> All:
>
> We have a Quad-Intel XEON 2.0GHz (1MB cache), 12GB memory, running
RH9, PG 7.4.0. There's
> an internal U320, 10K RPM RAID-10 setup on 4 drives.
>
> We are expecting a pretty high load, a few thousands of 'concurrent'
users executing either
> select, insert, update, statments.

> What is the next step up in terms of handling very heavy loads?
Clustering?

I'd look at adding more disks first. Depending on what type of query
load you get, that box sounds like it will be very much I/O bound. More
spindles = more parallell operations = faster under load. Consider
adding 15KRPM disks as well, they're not all that much more expensive,
and should give you better performance than 10KRPM.

Also, make sure you put your WAL disks on a separate RAIDset if possible
(not just a separate partition on existing RAIDset).

Finally, if you don't already have it, look for a battery-backed RAID
controller that can do writeback-cacheing, and enable that. (Don't even
think about enabling it unless it's battery backed!) And add as much RAM
as you can to that controller.

//Magnus