multiple postgresql servers in multiple jails?
Anton - Valqk
lists at lozenetz.org
Fri Oct 26 01:46:41 PDT 2007
You can alternatively set the SEM* and SHMMAX in the loader.conf.
I have a server runing two pgs.
#> cat /boot/loader.conf
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:
> By the way, "ipcs -bm" displays the shared memory segment
> > > 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
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