Re: Opinions on SSDs

On Mon, Aug 12, 2013 at 04:41:48PM -0400, David F. Skoll wrote:
> On Mon, 12 Aug 2013 16:05:04 -0400
> Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>
> > On Mon, Aug 12, 2013 at 08:33:04AM -0700, Joshua D. Drake wrote:
>
> > > Put the pg_xlog on spindles, they are more than fast enough and
> > > won't eat up the write life of your SSDs.
>
> > Given its small size and need for fast fsync, I have WAL on SSDs, and
> > the data on magnetic disk. You are right the WAL can generate a lot
> > of writes, but just use smartctl monitoring and replace the SSD when
> > needed.
>
> :-) Nothing like consensus from Pg luminaries. :)
>
> Anyway, I've decided to go with spinning disks for this server upgrade. The
> factors behind my decision:
>
> o A server with 16 10Krpm disks will be substantially better than what we
> have now, and what we have now is managing to keep up with only occasional
> over-busy periods.
>
> o My supplier cannot easily get the 320, 710 or S3700 Intel SSD disks; he
> claims a shortage of Intel SSD drives. I know too little about non-Intel
> SSDs to feel comfortable with them.
>
> o One of our two database servers is 200km away, so swapping out SSDs on
> a prophylactic basis is not particularly appetizing.

Good point on the travel distance. For my server, I didn't go with a
RAID controller with a battery-backed unit (BBU), so SSDs for WAL made
complete sense for me. FYI, your CPUs exactly matches mine:

http://momjian.us/main/blogs/pgblog/2012.html#January_20_2012

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +