On Wed, 2011-02-16 at 15:56 -0500, Greg Smith wrote: > Bryan Keller wrote: > > It sounds like NFS is a viable solution nowadays. I a still going to shoot for using iSCSI, given it is a block-level protocol rather than file-level, it seems to me it would be better suited to database I/O. > > > > Please digest carefully where Joe Conway pointed out that it took them > major kernel-level work to get NFS working reliably on Linux. On > anything but Solaris, I consider NFS a major risk still; nothing has > improved "nowadays" relative to when people used to report regular > database corruption running it on other operating systems. Make sure > you read > http://www.time-travellers.org/shane/papers/NFS_considered_harmful.html > and mull over the warnings in there before you assume it will work, too. > > I don't think I've ever heard from someone happy with an iSCSI > deployment, either. The only way you could make an NFS+iSCSI storage > solution worse is to also use RAID5 on the NAS. > > I'd suggest taking a look at > http://wiki.postgresql.org/wiki/Shared_Storage and consider how you're > going to handle fencing issues as well here. One of the reasons SANs > tend to be preferred in this area is because fencing at the > fiber-channel switch level is pretty straightforward. DAS running over > fiber-channel can offer the same basic features though, it's just not as > common to use a switch in that environment. In short, use DAS or a SAN. iSCSI suffers from all kinds of performance issues and NFS is just Michael Myers scary. With DAS systems able to handle up 192 drives over 6Gb/s a second these days, combined with a volume manager you can solve a lot of problems without breaking the bank. JD -- PostgreSQL.org Major Contributor Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579 Consulting, Training, Support, Custom Development, Engineering http://twitter.com/cmdpromptinc | http://identi.ca/commandprompt -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
