Date: Wed, 05 May 2010 16:33:34 +0100 From: Karl Pielorz <kpielorz_lst@tdx.co.uk> To: freebsd-questions@freebsd.org Subject: Is it safe to increase / double kern.maxvnodes under FreeBSD 6.4 i386? Message-ID: <D267FBBBB6495A70AA0FB082@HPQuadro64.dmpriest.net.uk>
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Hi, We had some issues at the weekend that left one of our machines with a very, very large sendmail queue... While we were trying to sort it out we noticed the machine takes over 4 minutes to go through the queue (i.e. 'mailq'). I noticed the machine was hovering around the maxvnode limit - so I upped it. The 'sweet spot' appears to be: sysctl -w kern.maxvnodes=250000 That cuts the time to run a mailq from over four minutes down to 12 seconds. The machine has 2Gb of RAM, and is 'moderately' loaded (normally) - is it wise to leave that setting at 250,000 - or is it likely to cause other issues (i.e. kernel memory issues) - is there any metric I can look at / check to see if we can get away with leaving it that high? The only stuff I can seem to find on the 'net mostly concerns upping it under amd64 as that uses a different mapping method for vnodes - I can't seem to find anything that covers increasing it that much (2.5 * the default of 100,000) under i386. As it obviously makes a huge difference for us, I'd love to leave it in place - but don't want to risk anything drastic like a panic. Thanks, -Karl
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