From Axel.Rau at chaos1.de Fri Aug 8 23:58:29 2008 From: Axel.Rau at chaos1.de (Axel Rau) Date: Fri Aug 8 23:58:36 2008 Subject: PostgreSQL 3.3 on gjournaled fs Message-ID: <8A4CC87D-8B69-4120-BB89-F794E4FFD871@Chaos1.DE> Hi, I'm starting migration of my PostgreSQL tablespaces to gjournaled fs on 7-stable. Dedicated box is Opteron with Areca. Any experiences or hints? 4GB journal provider? Axel --- From ivoras at freebsd.org Sat Aug 9 10:08:25 2008 From: ivoras at freebsd.org (Ivan Voras) Date: Sat Aug 9 10:08:32 2008 Subject: PostgreSQL 3.3 on gjournaled fs In-Reply-To: <8A4CC87D-8B69-4120-BB89-F794E4FFD871@Chaos1.DE> References: <8A4CC87D-8B69-4120-BB89-F794E4FFD871@Chaos1.DE> Message-ID: Axel Rau wrote: > Hi, > > I'm starting migration of my PostgreSQL tablespaces to gjournaled fs on > 7-stable. > Dedicated box is Opteron with Areca. > Any experiences or hints? > 4GB journal provider? The question is - why do you need gjournal? PostgreSQL (and other decent databases) does its own journaling (search for WAL), so using it on a journaled file system doesn't do much. If you really want it, it won't hurt you. Journal size needs to be scaled based on your load. If you have constant writes you need a larger journal. You need it to hold 20*(write_rate in MB/s) megabytes. E.g. if your array does 100 MB/s, you need a 2000 MB journal. This calculation is for default gjournal settings. You could put the journal on another drive or array for best performance. (Of course, you could skip gjournal and put the WAL on the other drive). -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 250 bytes Desc: OpenPGP digital signature Url : http://lists.freebsd.org/pipermail/freebsd-database/attachments/20080809/34db147b/signature.pgp From Axel.Rau at chaos1.de Sat Aug 9 14:01:53 2008 From: Axel.Rau at chaos1.de (Axel Rau) Date: Sat Aug 9 14:02:00 2008 Subject: PostgreSQL 3.3 on gjournaled fs In-Reply-To: References: <8A4CC87D-8B69-4120-BB89-F794E4FFD871@Chaos1.DE> Message-ID: <3B2D25A1-5A0D-4163-A248-E709ADD54CC5@Chaos1.DE> Am 09.08.2008 um 11:03 schrieb Ivan Voras: > The question is - why do you need gjournal? PostgreSQL (and other > decent databases) does its own journaling (search for WAL), so using > it on a journaled file system doesn't do much. I want to prevent from fsck on large filesystems after outage. > > > If you really want it, it won't hurt you. Journal size needs to be > scaled based on your load. If you have constant writes you need a > larger journal. You need it to hold 20*(write_rate in MB/s) > megabytes. E.g. if your array does 100 MB/s, you need a 2000 MB > journal. This calculation is for default gjournal settings. This is usefull info. > > > You could put the journal on another drive or array for best > performance. (Of course, you could skip gjournal and put the WAL on > the other drive). I have the latter, but intent to put this on gjournal too. Axel ---