Re: [GENERAL] openvz and shared memory trouble

On 03/28/2014 02:21 PM, Willy-Bas Loos wrote:
> Hi,
>
> I have a problem with postgres in combination with openvz.
> My hot standby crashes on me when i give it a normal value for
> shared_buffers (4GB, which 25% of the memory in the container).
> When i tune down the shared_buffers, it works again. But of course this is
> far from desireable.
>
> Now, i've seen a couple more messages around the net about openVZ and
> postgres that weren't very encouraging:
>
> http://www.postgresql.org/message-id/CAHyXU0xa5EgvjeH=4vp-eZDJdS5kMQuiDivvTRLjY-uZ62Y44w@mail.gmail.com
> http://www.postgresql.org/message-id/23206.1254683408@sss.pgh.pa.us
> http://postgresql.1045698.n5.nabble.com/BUG-9721-Fatal-error-on-startup-no-free-slots-in-PMChildFlags-array-td5797390.html
>
> But i am in a position where we already have a pretty strong binding with
> openVZ.
> I also have a colleague that has been using openVZ and postgres on
> production for quite a while now, without any problems. And already 1 of
> our servers is running a production database in openVZ that is well used,
> without any trouble of this kind.
>
> Now, what i would like to know is:
>
> - is there clarity about what the issues are at all
> - is it just 1 problem (in openVZ) that make openVZ and postgres so
> poorly compatible?
> - how can i stay out of trouble (when using postgres inside openVZ)

Try increasing the share memory "shmpages" of container from host.

> - who else has trouble with openVZ in combination with postgres, and
> what constitutes the trouble?
>
> regards,
>
> WBL
>
>