Re: The FAQ on fsync/O_SYNC

2015-04-21 Thread Chris Murphy
On Sun, Apr 19, 2015 at 10:27 PM, Zygo Blaxell wrote: > On Sun, Apr 19, 2015 at 10:31:02PM +0800, Craig Ringer wrote: >> I'm curious as to whether +C has any effect on BTRFS's durability, too. > > I would expect it to be strictly equal to or worse than the CoW > durability. It would have all the

Re: The FAQ on fsync/O_SYNC

2015-04-20 Thread Zygo Blaxell
On Mon, Apr 20, 2015 at 06:07:09AM +, Duncan wrote: > 4.0 is out. There's reason people may want to stick one version back by > default, to 3.19 currently, since it can take a few weeks for early > reports to develop into a coherent problem, and sticking one stable > series back allows for

Re: The FAQ on fsync/O_SYNC

2015-04-20 Thread Zygo Blaxell
On Mon, Apr 20, 2015 at 10:13:47AM +0200, Gian-Carlo Pascutto wrote: > On 20-04-15 06:27, Zygo Blaxell wrote: > > >> I'm curious as to whether +C has any effect on BTRFS's durability, too. > > > > I would expect it to be strictly equal to or worse than the CoW > > durability. > > In addition to

Re: The FAQ on fsync/O_SYNC

2015-04-20 Thread Gian-Carlo Pascutto
On 20-04-15 06:27, Zygo Blaxell wrote: >> I'm curious as to whether +C has any effect on BTRFS's durability, too. > > I would expect it to be strictly equal to or worse than the CoW > durability. In addition to the stuff pointed out, I've wondered about this: PostgreSQL full_page_writes copies 8

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Duncan
Zygo Blaxell posted on Mon, 20 Apr 2015 00:27:31 -0400 as excerpted: > Normal writes to btrfs filesystems using the versioned filesystem tree > are consistent(ish), atomic, and durable; however, they have high > latency as the filesystem normally delays commit until triggered by a > periodic timer

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Zygo Blaxell
On Sun, Apr 19, 2015 at 10:31:02PM +0800, Craig Ringer wrote: > On 19 April 2015 at 22:28, Martin Steigerwald wrote: > > Am Sonntag, 19. April 2015, 21:20:11 schrieb Craig Ringer: > >> Hi all > > > > Hi Craig, > > > >> I'm looking into the advisability of running PostgreSQL on BTRFS, and > >> afte

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Craig Ringer
While the discussion on -C was interesting, I'm really interested in btrfs's fsync() behaviour, per the original post: On 19 April 2015 at 21:20, Craig Ringer wrote: > Hi all > > I'm looking into the advisability of running PostgreSQL on BTRFS, and > after looking at the FAQ there's something I'm

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Hugo Mills
On Sun, Apr 19, 2015 at 08:41:39PM +0200, Martin Steigerwald wrote: > Am Sonntag, 19. April 2015, 18:18:24 schrieb Hugo Mills: > > On Sun, Apr 19, 2015 at 07:50:32PM +0200, Martin Steigerwald wrote: > > > Am Sonntag, 19. April 2015, 15:18:51 schrieb Hugo Mills: > > > > On Sun, Apr 19, 2015 at 05:10

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Martin Steigerwald
Am Sonntag, 19. April 2015, 18:18:24 schrieb Hugo Mills: > On Sun, Apr 19, 2015 at 07:50:32PM +0200, Martin Steigerwald wrote: > > Am Sonntag, 19. April 2015, 15:18:51 schrieb Hugo Mills: > > > On Sun, Apr 19, 2015 at 05:10:30PM +0200, Martin Steigerwald wrote: > > > > Am Sonntag, 19. April 2015, 2

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Hugo Mills
On Sun, Apr 19, 2015 at 07:50:32PM +0200, Martin Steigerwald wrote: > Am Sonntag, 19. April 2015, 15:18:51 schrieb Hugo Mills: > > On Sun, Apr 19, 2015 at 05:10:30PM +0200, Martin Steigerwald wrote: > > > Am Sonntag, 19. April 2015, 22:31:02 schrieb Craig Ringer: > > > > I'm curious as to whether +

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Martin Steigerwald
Am Sonntag, 19. April 2015, 15:18:51 schrieb Hugo Mills: > On Sun, Apr 19, 2015 at 05:10:30PM +0200, Martin Steigerwald wrote: > > Am Sonntag, 19. April 2015, 22:31:02 schrieb Craig Ringer: > > > On 19 April 2015 at 22:28, Martin Steigerwald > > > > wrote: > > > > Am Sonntag, 19. April 2015, 21:2

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Russell Coker
On Mon, 20 Apr 2015, Craig Ringer wrote: > PostgreSQL is its self copy-on-write (because of multi-version > concurrency control), so it doesn't make much sense to have the FS > doing another layer of COW. That's a matter of opinion. I think it's great if PostgreSQL can do internal checkums and e

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Hugo Mills
On Sun, Apr 19, 2015 at 05:10:30PM +0200, Martin Steigerwald wrote: > Am Sonntag, 19. April 2015, 22:31:02 schrieb Craig Ringer: > > On 19 April 2015 at 22:28, Martin Steigerwald > wrote: > > > Am Sonntag, 19. April 2015, 21:20:11 schrieb Craig Ringer: > > >> Hi all > > > > > > Hi Craig, > > >

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Martin Steigerwald
Am Sonntag, 19. April 2015, 22:31:02 schrieb Craig Ringer: > On 19 April 2015 at 22:28, Martin Steigerwald wrote: > > Am Sonntag, 19. April 2015, 21:20:11 schrieb Craig Ringer: > >> Hi all > > > > Hi Craig, > > > >> I'm looking into the advisability of running PostgreSQL on BTRFS, and > >> afte

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Craig Ringer
On 19 April 2015 at 22:28, Martin Steigerwald wrote: > Am Sonntag, 19. April 2015, 21:20:11 schrieb Craig Ringer: >> Hi all > > Hi Craig, > >> I'm looking into the advisability of running PostgreSQL on BTRFS, and >> after looking at the FAQ there's something I'm hoping you could >> clarify. >> >>

Re: The FAQ on fsync/O_SYNC

2015-04-19 Thread Martin Steigerwald
Am Sonntag, 19. April 2015, 21:20:11 schrieb Craig Ringer: > Hi all Hi Craig, > I'm looking into the advisability of running PostgreSQL on BTRFS, and > after looking at the FAQ there's something I'm hoping you could > clarify. > > The wiki FAQ says: > > "Btrfs does not force all dirty data to d