Question 1. We are going to use PostgreSQL 3.1 with FreeBSD. The pg docs say that it is better to use FreeBSD because it can alter the I/O priority of processes dynamically. The latest legacy release is 6.3 which is probably more stable. However, folks say that 7.0 has superior performance on the same hardware. Can I use 7.0 on a production server?
FreeBSD 7.x is pretty stable, and it has the advantage of having the new ULE and other things that can't be MFC'd to 6.x branch. And as a long time FreeBSD enthusiast having Cisco sponsoring Dtrace, Nokia sponsoring scheduler development etc. 7.x is definitely in my opinion now the branch to install and start following for ease of upgrading later. Of course, as always check that your intended hardware is supported.
ULE which is pretty much the key for performance boost in 7.x branch isn't yet the default scheduler, but will be in 7.1 and afterwards. This means you have to roll custom kernel if you want to use ULE.
Question 3. FreeBSD 7.0 can use the ZFS file system. I suspect that UFS 2 + soft updates will be better, but I'm not sure. Which is better?
For now I'd choose between UFS+gjournal or plain UFS, although with bigger disks journaling is a boon compared to fsck'ing plain UFS partition. ZFS isn't yet ready for production I think, but it seems to be getting there. This is opinion based on bug reports and discussions in stable and current mailing lists, not on personal testing though. My experiences with gjournal have been positive so far.
On the drives and controller - I'm not sure whether SCSI/SAS will give any noticeable boost over SATA, but based on personal experience SCSI is still ahead on terms of drive reliability. Whatever technology I'd choose, for production server getting decent battery backed controller would be the start. And of course a controller that does the RAID's in hardware.
-Reko
-- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
