multiple postgresql servers in multiple jails?

[Anton - Valqk]

You can alternatively set the SEM* and SHMMAX in the loader.conf.
I have a server runing two pgs.

#> cat /boot/loader.conf
kern.ipc.semmni=256
kern.ipc.semmns=512
kern.ipc.semmnu=256
kern.ipc.semmap=256

Oliver Fromme wrote:
> Oliver Peter wrote:
>  > Oliver Fromme wrote:
>  > > Oliver Peter wrote:
>  > > > Does anybody have a running system with more than one jail hosting
>  > > > more than one postgres server?
>  > > 
>  > > Yes, you must configure them to use different port numbers,
>  > > because the SysV IPC IDs are derived from the port number.
>  > > If you try to run both servers with the default port, you'll
>  > > get a conflict.  Configure different port numbers, and it
>  > > will work.
>  > 
>  > Thanks for that hint.  After changing the port numbers for each
>  > instance to a different one, it works - but only at first glance.
>  > After making some test creates and inserts to all servers at the same
>  > time I receive the 'out of memory' messages again...
>  > Different UIDs, different ports, same error.
>
> Can you please give the output from "ipcs -M" and "ipcs -p"?
>
> The latter shows the process IDs of the creator (CPID) and
> last user (LPID) of shared memory resources.  You can look
> up the jails in which those processes are running, so to
> make sure that none of the resources was taken over by a
> different jail.
>
> The "jps" script could be useful:
>
> http://www.secnetix.de/~olli/scripts/jps
>
> By the way, "ipcs -bm" displays the shared memory segment
> sizes.
>
>  > > By the way, the PostgreSQL developers do _not_ recommend to
>  > > run multiple servers on the same machine, because of bad
>  > > efficiency.  It is much better (performance-wise) to run
>  > > all databases within the same server engine.  PostgreSQL
>  > > has all the authentication and permission features you need
>  > > to separate multiple databases within a single server, so
>  > > there is really no need to use multiple jails.
>  > 
>  > Of course I understand that.  But I would like to setup a test server
>  > in a different jail beside my production jail/pgsql-server to be sure
>  > not to crash my production server.
>  > Performance does not matter (at this time in this specific case of
>  > course!).
>
> I see.  In that case it is probably OK.
>
>  > > I have these on a machine with a single PostgreSQL server,
>  > > as per recommendations of the developers:
>  > > 
>  > > options         SHMMAXPGS=65536
>  > > options         SEMMAP=1024
>  > > options         SEMMNI=64
>  > > options         SEMMNS=1024
>  > > options         SEMUME=64
>  > > options         SEMMNU=128
>  > 
>  > Is this a good recommendation for a machine with only 1GB of RAM?
>
> In fact, the above lines are from a machine with 256 MB RAM.
> For 1 GB you can probably double the number of shared memory
> pages (SHMMAXPGS value).  The semaphore values (SEM*) should
> be sufficient in either case, I think.
>
> Best regards
>    Oliver
>
>   


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