On Fri, Dec 20, 2013 at 7:10 AM, Shaun Thomas <stho...@optionshouse.com>wrote:
> On 12/19/2013 04:06 PM, Dave Johansen wrote: > > Right now, we're running a RAID 1 for pg_clog, pg_log and pg_xlog and >> then a RAID 1+0 with 12 disks for the data. Would there be any benefit >> to running a separate RAID 1+0 with a tablespace for the indexes? >> > > Not really. PostgreSQL doesn't currently support parallel backend fetches, > aggregation, or really anything. It's looking like 9.4 will get us a lot > closer to that, but right now, everything is serial. > > Serial or not, separate backends will have separate read concerns, and > PostgreSQL 9.2 and above *do* support index only scans. So theoretically, > you might actually see some benefit there. If it were me and I had spindles > available, I would just increase the overall size of the pool. It's a lot > easier than managing multiple tablespaces. > Ok, that makes sense. Is there a benefit to having the WAL and logs on the separate RAID 1? Or is just having them be part of the larger RAID 1+0 just as good?
