Subject: Re: [vserver] Shared Memory
From: Holger Amann <keeney@fehu.org>
Date: Thu, 29 Oct 2009 01:20:12 +0100


Am 29.10.2009 um 01:00 schrieb Lukasz Czarnowski:

> I had the same experience with kernel 2.6.22.x-vs2.2.x and pgsql 8.1  
> - shmem is counted several times.

I played with the shared memory example shown at [1] and it seems,  
that in general everything is working fine, except Postgres.
So, until someone is able to fix this, Linux vServer and Postgres ->  
Don't do it! :(

guest1:/# /etc/init.d/postgresql-8.4 start
Starting PostgreSQL 8.4 database server: main.
guest1:/# ipcs

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status

------ Semaphore Arrays --------
key        semid      owner      perms      nsems

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages

guest1:/# ./shmserver

(from another console)
guest1:~# ipcs

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x0000162e 65537      root      666        27         1

------ Semaphore Arrays --------
key        semid      owner      perms      nsems

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages

guest1:~# ./shmclient
abcdefghijklmnopqrstuvwxyz

q.e.d.

[1] http://www.cs.cf.ac.uk/Dave/C/node27.html