> Just to add to the conversation, there's no real advantage to putting
> WAL on SSD. Indexes can benefit from them, but WAL is mosty
> seqwuential throughput and for that a pair of SATA 1TB drives at
> 7200RPM work just fine for most folks.
Actually, there's a strong disadvantage to putting WAL on SSD. SSD is
very prone to fragmentation if you're doing a lot of deleting and
replacing files. I've implemented data warehouses where the database
was on SSD but WAL was still on HDD.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com