Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Keith Fiske
On Wed, Sep 30, 2015 at 4:58 PM, Benjamin Smith wrote: > On Wednesday, September 30, 2015 03:49:44 PM Keith Fiske wrote: > > We've run postgres on ZFS for years with great success (first on > > OpenSolaris, now on OmniOS, and I personally run it on FreeBSD). The > > snapshotting feature makes upg

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Benjamin Smith
On Wednesday, September 30, 2015 03:49:44 PM Keith Fiske wrote: > We've run postgres on ZFS for years with great success (first on > OpenSolaris, now on OmniOS, and I personally run it on FreeBSD). The > snapshotting feature makes upgrades on large clusters much less scary > (snapshot and revert if

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Benjamin Smith
On Wednesday, September 30, 2015 09:58:08 PM Tomas Vondra wrote: > On 09/30/2015 07:33 PM, Benjamin Smith wrote: > > On Wednesday, September 30, 2015 02:22:31 PM Tomas Vondra wrote: > >> I think this really depends on the workload - if you have a lot of > >> random writes, CoW filesystems will perf

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Tomas Vondra
On 09/30/2015 03:45 PM, Patric Bechtel wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi Tomas, Tomas Vondra schrieb am 30.09.2015 um 14:01: Hi, ... I've also done a few runs with compression, but that reduces the performance a bit (understandably). I'm somewhat surprised by the

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Tomas Vondra
On 09/30/2015 07:33 PM, Benjamin Smith wrote: On Wednesday, September 30, 2015 02:22:31 PM Tomas Vondra wrote: I think this really depends on the workload - if you have a lot of random writes, CoW filesystems will perform significantly worse than e.g. EXT4 or XFS, even on SSD. I'd be curious

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Keith Fiske
On Tue, Sep 29, 2015 at 1:01 PM, Benjamin Smith wrote: > Does anybody here have any recommendations for using PostgreSQL 9.4 > (latest) > with ZFS? > > We've been running both on ZFS/CentOS 6 with excellent results, and are > considering putting the two together. In particular, the CoW nature (an

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Benjamin Smith
On Wednesday, September 30, 2015 02:22:31 PM Tomas Vondra wrote: > I think this really depends on the workload - if you have a lot of > random writes, CoW filesystems will perform significantly worse than > e.g. EXT4 or XFS, even on SSD. I'd be curious about the information you have that leads you

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Patric Bechtel
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi Tomas, Tomas Vondra schrieb am 30.09.2015 um 14:01: > Hi, > > On 09/30/2015 12:21 AM, Patric Bechtel wrote: >> -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 >> >> Hi Benjamin, >> >> if you're using compression, forget about that. You need to syn

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Tomas Vondra
Hi, On 09/29/2015 07:01 PM, Benjamin Smith wrote: Does anybody here have any recommendations for using PostgreSQL 9.4 (latest)with ZFS? I think this really depends on the workload - if you have a lot of random writes, CoW filesystems will perform significantly worse than e.g. EXT4 or XFS, ev

Re: [GENERAL] Postgresql 9.4 and ZFS?

2015-09-30 Thread Tomas Vondra
Hi, On 09/30/2015 12:21 AM, Patric Bechtel wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi Benjamin, if you're using compression, forget about that. You need to synchronize the ashift value to the internal rowsize of you SSD, that's it. Make sure your SSD doesn't lie to you regarding w