Date: Mon, 26 May 2003 13:12:44 -0300 (ADT) From: "Marc G. Fournier" <scrappy@hub.org> To: Mike Harding <mvh@ix.netcom.com> Cc: stable@freebsd.org Subject: Re: system slowdown - vnode related Message-ID: <20030526130556.G56519@hub.org> In-Reply-To: <1053964809.7831.6.camel@netcom1.netcom.com> References: <20030521171941.364325314@netcom1.netcom.com> <20030524190051.R598@hub.org><20030526123617.D56519@hub.org> <1053964809.7831.6.camel@netcom1.netcom.com>
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On Mon, 26 May 2003, Mike Harding wrote:
> Er - are any changes made to RELENG_4_8 that aren't made to RELENG_4? I
> thought it was the other way around - that 4_8 only got _some_ of the
> changes to RELENG_4...
Ack, my fault ... sorry, wasn't thinking :( RELENG_4 is correct ... I
should have confirmed my settings before blathering on ...
One of the scripts I used extensively while debugging this ... a quite
simple one .. was:
#!/bin/tcsh
while ( 1 )
echo `sysctl debug.numvnodes` - `sysctl debug.freevnodes` - `sysctl debug.vnlru_nowhere` - `ps auxl | grep vnlru | grep -v grep | awk '{print $20}'`
sleep 10
end
which outputs this:
debug.numvnodes: 463421 - debug.freevnodes: 220349 - debug.vnlru_nowhere: 3 - vlruwt
I have my maxvnodes set to 512k right now ... now, when the server "hung",
the output would look something like (this would be with 'default' vnodes):
debug.numvnodes: 199252 - debug.freevnodes: 23 - debug.vnlru_nowhere: 12 - vlrup
with the critical bit being the vlruwt -> vlrup change ...
with unionfs, you are using two vnodes per file, instead of one in
non-union mode, which is why I went to 512k vs the default of ~256k vnodes
... it doesn't *fix* the problem, it only reduces its occurance ...
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