On Mon, Jun 29, 2009 at 11:19 PM, Brian Modra<epailty@xxxxxxxxxxxxxx> wrote: > Hi, > my database requires 1TB of disk space, but I want to avoid RAID (e.g. > 8x 300GB SAS drives in RAID 10), and use rather a 1TB SATA disk. > To avoid the "slowness" of SATA showing in queries, I want to cache > lots of the database, but I don't want to buy more than 16GB RAM. > (Budget limits). > So I'm considering configuring a large cache, requiring larger than > 16GB, and allowing it to "spill over" into swap space on a single > 300GB SAS drive. No, spilling to swap will make it slower than just hitting the drives. If you're on a budget, look into using 4 1TB to 1.5TB SATA drives (they're pretty cheap) with linux software RAID. You can get pretty good read performance from a RAID-10 of 4 drives, better parallel performance. Also, I was pricing RAM today for a server, and the difference between 16 and 32Gig ($350 or so) was so little I didn't even consider going with 16G. Still, 16 or 32, it's only a tiny portion of the 1TB you're talking about storing and accessing. If it's gonna be read-mostly, then leaving out the RAID controller can save you a lot of money. You can buy a 4 x 1TB drive machine with quad core opteron and 16Gig for about $2500, $2850 if you want 32Gig. That's a good deal for a machine with redundancy on the drives and good performance. -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
