Not sure if the kernel shared memory segment size is appropriate, you are allocating all your memory to the chunk. With 32GB memory, effective_cache_size can be raised, higher, and you can go down on shared_buffers. Check this: http://www.varlena.com/varlena/GeneralBits/Tidbits/annotated_conf_e.html -anjan -----Original Message----- From: Tomeh, Husam [mailto:htomeh@xxxxxxxxxxx] Sent: Wed 12/14/2005 5:08 PM To: pgsql-admin@xxxxxxxxxxxxxx Cc: Tom Lane Subject: [ADMIN] PG 8.1.1 Cannot allocate shared_buffers memory error I just installed postgres 8.1.1 on a dual optron Linux box running Linux 4 advanced server, with 32GB of RAM and 2GB of swap. I'm trying to allocate 24 GB as shared_bufferes. I'm getting an error that I can not allocate memory (see below). If I change my shared_buffers to 16GB, postgres starts up with no issue. I'm trying to understand why I'm getting the shared memory error at sizes above 16GB whilst I have 32GB with appropriate (I think) settings of kernel parameters. Any help is appreciated. Thanks... My sysctl.conf has : kernel.shmmax = 34359738368 kernel.shmall = 34359738368 (32GB). And here's some of related postgresql.conf parameters: shared_buffers = 2359296 work_mem = 16384 maintenance_work_mem = 2097152 max_connections = 100 effective_cache_size = 2621440 --- Error: FATAL: could not create shared memory segment: Cannot allocate memory [2005-12-14 13:56:03 PST|||] DETAIL: Failed system call was shmget(key=5432001, size=19760111616, 03600). [2005-12-14 13:56:03 PST|||] HINT: This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory or swap space. To reduce the request size (currently 19760111616 bytes), reduce PostgreSQL's shared_buffers parameter (currently 2359296) and/or its max_connections parameter (currently 100). --- Regards, Husam Tomeh ********************************************************************** This message contains confidential information intended only for the use of the addressee(s) named above and may contain information that is legally privileged. If you are not the addressee, or the person responsible for delivering it to the addressee, you are hereby notified that reading, disseminating, distributing or copying this message is strictly prohibited. If you have received this message by mistake, please immediately notify us by replying to the message and delete the original message immediately thereafter. Thank you. FADLD Tag ********************************************************************** ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
