Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS
Date
Msg-id 20180417213245.GC13097@momjian.us
Whole thread Raw
In response to Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Responses Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS
List pgsql-hackers
On Mon, Apr  9, 2018 at 03:42:35PM +0200, Tomas Vondra wrote:
> On 04/09/2018 12:29 AM, Bruce Momjian wrote:
> > 
> > An crazy idea would be to have a daemon that checks the logs and
> > stops Postgres when it seems something wrong.
> > 
> 
> That doesn't seem like a very practical way. It's better than nothing,
> of course, but I wonder how would that work with containers (where I
> think you may not have access to the kernel log at all). Also, I'm
> pretty sure the messages do change based on kernel version (and possibly
> filesystem) so parsing it reliably seems rather difficult. And we
> probably don't want to PANIC after I/O error on an unrelated device, so
> we'd need to understand which devices are related to PostgreSQL.

Replying to your specific case, I am not sure how we would use a script
to check for I/O errors/space-exhaustion if the postgres user doesn't
have access to it.  Does O_DIRECT work in such container cases?

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +


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