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:[EMAIL PROTECTED]
Sent: Wed 12/14/2005 5:08 PM
To: pgsql-admin@postgresql.org
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
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