Re: FileFallocate misbehaving on XFS

Hi,

On 2024-12-09 18:34:22 +1100, Michael Harris wrote:
> Our application has recently migrated to PG16, and we have experienced
> some failed upgrades. The upgrades are performed using pg_upgrade and
> have failed during the phase where the schema is restored into the new
> cluster, with the following error:
>
> pg_restore: error: could not execute query: ERROR: could not extend
> file "pg_tblspc/16401/PG_16_202307071/17643/1249.1" with
> FileFallocate(): No space left on device
> HINT: Check free disk space.

Were those pg_upgrades done with pg_upgrade --clone? Or have been, on the same
filesystem, in the past?

The reflink stuff in xfs (which is used to implement copy-on-write for files)
is somewhat newer and you're using somewhat old kernels:

> We have seen this on both Rocky Linux 8 (kernel 4.18.0) and Rocky
> Linux 9 (Kernel 5.14.0).

I found some references for bugs that were fixed in 5.13. But I think at least
some of this would persist if the filesystem ran into the issue with a kernel
before those fixes. Did you upgrade "in-place" from Rocky Linux 8?

> I am wondering if this bug might be related:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1791323

Doubt it, we never do this as far as I am aware.

Greetings,

Andres Freund