On Mon, Jan 26, 2009 at 4:09 AM, Matthew Wakeling <matthew@xxxxxxxxxxx> wrote: > On Sun, 25 Jan 2009, Scott Marlowe wrote: >> >> More cores is more important than faster but fewer >> >> Again, more slower disks > fewer slower ones. > > Not necessarily. It depends what you are doing. If you're going to be > running only one database connection at a time, doing really big complex > queries, then having really fast CPUs and discs is better than having lots. > However, that situation is rare. If backup/restore times are important, having a fast CPU is important because backup/restore is single threaded and unable to use more than one CPU. OK, two CPUs, one for the pg_dump process and one for the postgres daemon - but who buys anything with less than two cores these days? We do daily backups of our databases, and although our biggest isn't very large at approximately 15GB, backups take a bit more than an hour with one CPU maxed out. This system has two Xeon 5130 @ 2GHz, so even with the fastest processors, we can only reduce backup times by at most 50%. During normal workloads, processing hundreds of queries a second, system utilization stays below 10% on average - so for us, fewer cores that are faster would be a better purchase than more cores that are slower. Lots of people have databases much, much, bigger - I'd hate to imagine have to restore from backup from one of those monsters. -Dave -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
