[Users] Installation problem

[Steve Gordon]

----- Original Message -----
> From: "Joop" <jvdwege at xs4all.nl>
> To: "Dave Neary" <dneary at redhat.com>
> Cc: "users" <users at ovirt.org>
> Sent: Friday, September 21, 2012 9:57:02 AM
> Subject: Re: [Users] Installation problem
> 
> Dave Neary wrote:
> >
> >
> > It turns out, in /var/log/messages, that I have these error
> > messages:
> >> Sep 21 14:00:59 clare pg_ctl[5298]: FATAL:  could not create
> >> shared
> >> memory segment: Invalid argument
> >> Sep 21 14:00:59 clare pg_ctl[5298]: DETAIL:  Failed system call
> >> was
> >> shmget(key=5432001, size=36519936, 03600).
> >> Sep 21 14:00:59 clare pg_ctl[5298]: HINT:  This error usually
> >> means
> >> that PostgreSQL's request for a shared memory segment exceeded
> >> your
> >> kernel's SHMMAX parameter.  You can either reduce the request size
> >> or
> >> reconfigure the kernel with larger SHMMAX.  To reduce the request
> >> size (currently 36519936 bytes), reduce PostgreSQL's shared memory
> >> usage, perhaps by reducing shared_buffers or max_connections.
> >> Sep 21 14:00:59 clare pg_ctl[5298]: If the request size is already
> >> small, it's possible that it is less than your kernel's SHMMIN
> >> parameter, in which case raising the request size or reconfiguring
> >> SHMMIN is called for.
> >> Sep 21 14:00:59 clare pg_ctl[5298]: The PostgreSQL documentation
> >> contains more information about shared memory configuration.
> >> Sep 21 14:01:03 clare pg_ctl[5298]: pg_ctl: could not start server
> >> Sep 21 14:01:03 clare pg_ctl[5298]: Examine the log output.
> >> Sep 21 14:01:03 clare systemd[1]: postgresql.service: control
> >> process
> >> exited, code=exited status=1
> >> Sep 21 14:01:03 clare systemd[1]: Unit postgresql.service entered
> >> failed state.
> >
> > I increased the kernel's SHMMAX, and engine-cleanup worked
> > correctly.
> >
> > Has anyone else experienced this issue?
> Yes, not related to oVirt but on a database server also running
> Postgres. It seems that either the package maintainer is very
> conservative or postgres itself is. Standard on the Debian 6 server
> was
> also very low shmmax.
> What is the OS you run ovirt-engine on?

I'm going to take a stab and guess Fedora. This came up for an unrelated reason in #fedora-devel the other day, because Fedora (and I suspect Debian as well) has a policy of sticking as close to upstream as possible it uses the shmmax of the upstream kernel - which is as you note quite low. In RHEL and other EL6 derivatives this value is modified and set much higher.

Steve