Re: New server: SSD/RAID recommendations?

On Wed, Jul 1, 2015 at 6:06 PM, Craig James <cjames(at)emolecules(dot)com> wrote:
> We're buying a new server in the near future to replace an aging system. I'd
> appreciate advice on the best SSD devices and RAID controller cards
> available today.
>
> The database is about 750 GB. This is a "warehouse" server. We load supplier
> catalogs throughout a typical work week, then on the weekend (after Q/A),
> integrate the new supplier catalogs into our customer-visible "store", which
> is then copied to a production server where customers see it. So the load is
> mostly data loading, and essentially no OLTP. Typically there are fewer than
> a dozen connections to Postgres.
>
> Linux 2.6.32
> Postgres 9.3
> Hardware:
> 2 x INTEL WESTMERE 4C XEON 2.40GHZ
> 12GB DDR3 ECC 1333MHz
> 3WARE 9650SE-12ML with BBU
> 12 x 1TB Hitachi 7200RPM SATA disks
> RAID 1 (2 disks)
> Linux partition
> Swap partition
> pg_xlog partition
> RAID 10 (8 disks)
> Postgres database partition
>
> We get 5000-7000 TPS from pgbench on this system.
>
> The new system will have at least as many CPUs, and probably a lot more
> memory (196 GB). The database hasn't reached 1TB yet, but we'd like room to
> grow, so we'd like a 2TB file system for Postgres. We'll start with the
> latest versions of Linux and Postgres.
>
> Intel's products have always received good reports in this forum. Is that
> still the best recommendation? Or are there good alternatives that are price
> competitive?

In my opinion, the intel S3500 still has incredible value. Sub 1$/gb
and extremely fast. Heavily used both on production systems I manage
and my personal workstation. This report:
http://lkcl.net/reports/ssd_analysis.html told me everything I needed
to know about the drive. If you are sustaining extremely high rates
of writing data though particularly of the random kind, you need to
factor in drive lifespan and may want to consider the S3700 or one of
it's competitors. Both drives have been refreshed into the 3510 and
3710 modes but they are brand new and not highly reviewed so tread
carefully. On my crapbox workstation I get about 5k random writes on
large scale factor from a single device.

I definitely support software raid and not picking up a fancy raid
controller as long as you know your way around mdadm. Oh, and be
sure to crank effective_io_concurrency:
http://www.postgresql.org/message-id/CAHyXU0wgpE2E3B+rmZ959tJT_adPFfPvHNqeA9K9mkJRAT9HXw@mail.gmail.com

merlin