| From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Peter Geoghegan <pg(at)heroku(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Remove fsync ON/OFF as a visible option? |
| Date: | 2015-03-23 20:42:38 |
| Message-ID: | 20150323204238.GA28015@awork2.anarazel.de |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2015-03-22 12:54:37 -0700, Josh Berkus wrote:
> On 03/22/2015 06:45 AM, Andres Freund wrote:
> > FWIW, I think that's a myth. One I heard various versions of by now. As
> > long as the OSs page size (4kb nearly everywhere) is different from
> > postgres' (8kb) you can have torn pages. Even if individual filesystem
> > page writes are atomic.
>
> ZFS's block size is larger than Linux's memory page size. That is, ZFS
> on Linux uses a 8kB to 128kB block size depending on which blocks you're
> looking at and how you have it configured. Does that make a difference
> at all, given that Linux's memory page size is still 4kB?
No, it does not make a differencen. The page cache is still 4kb.
> FYI, the BTRFS folks are also claiming to be torn-page-proof, so it
> would be really nice to settle this. Not sure how to force the issue
> through testing though.
I don't think this applies here.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Jim Nasby | 2015-03-23 20:59:01 | Re: GSoC 2015: Extra Jsonb functionality |
| Previous Message | Peter Geoghegan | 2015-03-23 20:14:28 | Re: Abbreviated keys for Numeric |