Re: 15 pg_upgrade with -j - Mailing list pgsql-general

From Peter J. Holzer
Subject Re: 15 pg_upgrade with -j
Date
Msg-id 20230523171929.5e3j56nbvaicexih@hjp.at
Whole thread Raw
In response to Re: 15 pg_upgrade with -j  (Ron <ronljohnsonjr@gmail.com>)
Responses Re: 15 pg_upgrade with -j  (Ron <ronljohnsonjr@gmail.com>)
List pgsql-general
On 2023-05-22 21:10:48 -0500, Ron wrote:
> On 5/22/23 18:42, Tom Lane wrote:
> > It looks like the assumption was that issuing link()
> > requests in parallel wouldn't help much but just swamp your disk
> > if they're all on the same filesystem.
> > Maybe that could use rethinking, not sure.
>
> It does need rethinking in the era of VMs and SANs. /var/lib/pgsql/15 is
> going to be on a different LUN from /var/lib/pgsql/9.6

You can't hardlink between different file systems.

Even if you could assign single directories to specific LUNs (does any
file system allow this?) this would at best spread the updates across
two LUNs (the inodes would presumable stay on the source LUN and the
target directory would be on the target LUN).

        hp

--
   _  | Peter J. Holzer    | Story must make more sense than reality.
|_|_) |                    |
| |   | hjp@hjp.at         |    -- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |       challenge!"

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