Re: ZFS filesystem - supported ?

2021-10-24 Thread Laura Smith
‐‐‐ Original Message ‐‐‐

On Saturday, October 23rd, 2021 at 18:48, Mladen Gogala 
 wrote:

> On 10/23/21 09:37, Laura Smith wrote:
>
> > Hi Mladen,
> >
> > Yes indeed, snapshots is the primary reason, closely followed by 
> > zfssend/receive.
> >
> > I'm no stranger to using LVM snapshots with ext4/xfs but it requires a 
> > custom shell script to manage the whole process around backups. I feel the 
> > whole thing could well be a lot cleaner with zfs.
> >
> > Thank you for the links, I will take a look.
> >
> > Laura
>
> Yes, ZFS is extremely convenient. It's a volume manager and a file
>
> system, all rolled into one, with some additiional convenient tools.
>
> However, performance is a major concern. If your application is OLTP,
>
> ZFS might be a tad too slow for your performance requirements. On the
>
> other hand, snapshots can save you  a lot of time with backups,
>
> especially if you have some commercial backup capable of multiple
>
> readers. If your application is OLTP, ZFS might be a tad too slow for
>
> your performance requirements. The only way to find out is to test. The
>
> ideal tool for testing is pgio:
>
> https://kevinclosson.net/2019/09/21/announcing-pgio-the-slob-method-for-postgresql-is-released-under-apache-2-0-and-available-at-github/
>
> For those who do not know, Kevin Closson was the technical architect who
>
> has built both Exadata and EMC XTRemIO. He is now the principal engineer
>
> of the Amazon RDS. This part is intended only for those who would tell
>
> him that "Oracle has it is not good enough" if he ever decided to post here.
>
>


Thank you Mladen for your very useful food for thought.

I think my plan going forward will be to stick to the old XFS+LVM setup and 
(maybe) when I have some more time on my hands fire up a secondary instance 
with ZFS and do some experimentation with pgio.

Thanks again !




Re: [Major version upgrade] pg_upgrade fails despite passing check mode

2021-10-24 Thread Abhishek Bhola
Thanks, let me try that out.

But is there a way to know for sure if pg_upgrade will have any such
problems?
Other than FDW's owner, any other things I should check before upgrading
other clusters?

Regards
Abhishek Bhola

On Sat, Oct 23, 2021 at 12:20 AM Laurenz Albe 
wrote:

> On Fri, 2021-10-22 at 17:11 +0900, Abhishek Bhola wrote:
> > postgres@dxxxpgs03:/D1/datadg/data13$ /usr/pgsql-13/bin/pg_upgrade
> -k --check
> >   --new-datadir='/D1/datadg/data13'
> --old-datadir='/D1/datadg/data'
> >   --new-bindir='/usr/pgsql-13/bin' --old-bindir='/usr/pgsql-11/bin'
> >
> > *Clusters are compatible*
> >
> > But then while performing the actual upgrade, it failed saying the
> "owner of a FDW should be a super user"
> >
> > So I started the old Postgres 11 again, changed the owner of that FDW to
> a super user.
> >
> > Now when I try to run the upgrade (even in check mode) again, it says
> "new cluster tablespace directory already exists"
> >
> > Is it safe to delete the new tablespace directories?
>
> Don't remove the tablespace directories, because they contain the original
> data from the
> old cluster.  But there should be directories called PG_13_202007201, and
> you have to
> remove those.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>
>

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