Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WXva5-0008Io-Ah for pgsql-performance@arkaria.postgresql.org; Wed, 09 Apr 2014 16:42:33 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1WXva4-0004iq-0L for pgsql-performance@arkaria.postgresql.org; Wed, 09 Apr 2014 16:42:32 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WXva2-0004if-NR for pgsql-performance@postgresql.org; Wed, 09 Apr 2014 16:42:30 +0000 Received: from momjian.us ([72.94.173.45]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WXvZy-00010C-Uu for pgsql-performance@postgresql.org; Wed, 09 Apr 2014 16:42:30 +0000 Received: from bruce by momjian.us with local (Exim 4.72) (envelope-from ) id 1WXvZv-0005i8-EI; Wed, 09 Apr 2014 12:42:23 -0400 Date: Wed, 9 Apr 2014 12:42:23 -0400 From: Bruce Momjian To: Shaun Thomas Cc: 'Reza Taheri' , "pgsql-performance@postgresql.org" Subject: Re: PGSQL, checkpoints, and file system syncs Message-ID: <20140409164223.GB8686@momjian.us> References: <66CE997FB523C04E9749452273184C6C19DAC05908@exch-mbx-113.vmware.com> <0683F5F5A5C7FE419A752A034B4A0B97978B5EBE@sswchi5pmbx2.peak6.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0683F5F5A5C7FE419A752A034B4A0B97978B5EBE@sswchi5pmbx2.peak6.net> User-Agent: Mutt/1.5.20 (2009-06-14) X-Pg-Spam-Score: -2.2 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org On Tue, Apr 8, 2014 at 02:00:05PM +0000, Shaun Thomas wrote: > So if you are on a 1GB RAID card, set it to 1GB. Once you have 1GB > of dirty memory (from a checkpoint or whatever), Linux will begin > flushing. > > This is a pretty well-known issue on Linux systems with large amounts > of RAM. Most VM servers fit that profile, so I'm not surprised it's > hurting you. Agreed. The dirty kernel defaults Linux defaults are too high for systems with large amounts of memory. See sysclt -a | grep dirty for a list. -- Bruce Momjian http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance