Re: regarding PG on ZFS performance - Mailing list pgsql-admin

From Scott Ribe
Subject Re: regarding PG on ZFS performance
Date
Msg-id CD93C6F7-ABB9-4D8E-BB1B-A517B6B00EF9@elevated-dev.com
Whole thread Raw
In response to regarding PG on ZFS performance  (Scott Ribe <scott_ribe@elevated-dev.com>)
Responses Re: regarding PG on ZFS performance  (Scott Ribe <scott_ribe@elevated-dev.com>)
List pgsql-admin
> On Apr 12, 2022, at 10:54 AM, Gogala, Mladen (Short Hills) <mladen.gogala@Fiserv.com> wrote:
>
> I wouldn’t call turning off data safety “a proper tuning”. It may be faster but can never be deployed to production.

As I explained, that which it protects against cannot happen on a ZFS volume. Therefore turning it off is just fine.

(ZFS fsync operations are themselves atomic, using its own write-ahead log. So full_page_writes does a double write to
avoidcorruption, but so does ZFS, thus 4X writes, and a major source of slowness. There is NO danger in letting only
oneof the two do a double-write in order to avoid a partial write ever being read back.) 


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