Re: [HACKERS] Funny WAL corruption issue

Hi Chris,

> I ran into a funny situation today regarding PostgreSQL replication and
> wal corruption and wanted to go over what I think happened and what I
> wonder about as a possible solution.

Sad story. Unfortunately I have no idea what could be a reason nor can I
suggest a good way to find it unless there is an already know sequence
of steps that reproduces an issue.

I just wanted to point out that a hardware issue or third party software
issues (bugs in FS, software RAID, ...) could not be fully excluded from
the list of suspects. According to the talk by Christophe Pettus [1]
it's not that uncommon as most people think.

If the issue reproduces from time to time on one replica and doesn't on
the second identical replica there is a good chance that you've faced a
hardware issue. Another thing that is worth checking is a SMART status
of the hard drive.

[1]: http://www.pgcon.org/2017/schedule/attachments/453_corruption-pgcon-2017.pdf

--
Best regards,
Aleksander Alekseev