Re: SSD + RAID

Craig James wrote:
> I've wondered whether this would work for a read-mostly application: Buy
> a big RAM machine, like 64GB, with a crappy little single disk. Build
> the database, then make a really big RAM disk, big enough to hold the DB
> and the WAL. Then build a duplicate DB on another machine with a decent
> disk (maybe a 4-disk RAID10), and turn on WAL logging.
>
> The system would be blazingly fast, and you'd just have to be sure
> before you shut it off to shut down Postgres and copy the RAM files back
> to the regular disk. And if you didn't, you could always recover from
> the backup. Since it's a read-mostly system, the WAL logging bandwidth
> wouldn't be too high, so even a modest machine would be able to keep up.

Should work, but I don't see any advantage over attaching the RAID array
directly to the 1st machine with the RAM and turning synchronous_commit=off.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com