Re: SSD + RAID - Mailing list pgsql-performance

From Heikki Linnakangas
Subject Re: SSD + RAID
Date
Msg-id 4B0067B0.2090407@enterprisedb.com
Whole thread Raw
In response to Re: SSD + RAID  (Craig James <craig_james@emolecules.com>)
List pgsql-performance
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

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