Re: WAL & ZFS

!=. Journal filesystem is only going to journal the metadata.  ZFS will guarantee the your WAL page is either written
ornot.  That is not the case with a journaled filesystem.   

I wouldn’t recommend doing that; if you are using ZFS then use it for both data and WALs.



> On Mar 31, 2022, at 6:47 PM, Holger Jakobs <holger@jakobs.com> wrote:
>
> The WAL is a journal itself and doesn't need another journal for safety. Therefore, a common recommendation is using
ext2(which has no journal) for the WAL partition. 
>
> Is this correct?
>
> Am 31.03.22 um 23:32 schrieb Rui DeSousa:
>> I would recommend a separate pg_wal filesystem with the record size to match the WAL page size; in my case 16k.  I
havekeep the default record size at 128k for the data volume and that configuration has worked well for supporting
largeDSS while using 16k data blocks. 
>>
>>> On Mar 30, 2022, at 5:32 PM, Scott Ribe <scott_ribe@elevated-dev.com> wrote:
>>>
>>> I've read all the info I could find re running PG on ZFS: turn off full page writes, turn on lz4, tweak recordsize
soas to take advantage of compression, etc. One thing I haven't seen is whether a separate volume for WAL would benefit
froma larger recordsize. Or any other tweaks??? 
>>>
>>> --
>>> Scott Ribe
>>> scott_ribe@elevated-dev.com
>>> https://www.linkedin.com/in/scottribe/
>>>
>>>
>>>
>>>
>>>
>>
>>
> --
> Holger Jakobs, Bergisch Gladbach, Tel. +49-178-9759012
>