[mythtv-users] pdflush is killing me

Brian Wood beww at beww.org
Tue Feb 6 00:34:27 UTC 2007

On Feb 5, 2007, at 5:21 PM, Mark Lehrer wrote:

> On Tue, Feb 06, 2007 at 08:20:18AM +1100, Nick Tan wrote:
>> According to the kernel documentation, pdflush periodically wakes  
>> up and
>> flushes old data to disk.  On one of my servers it was set to 5  
>> seconds.
>>  Here's what I found in the kernel docs:
> FYI, here is a cut & paste from another discussion about this; I
> can't wait to get home and try it out:
>> Experience with Ext3 data journaling indicates that dropping  
>> expire/writeback
>> can help to smooth out I/O:
>> vm.dirty_expire_centisecs = {300-1000}
>> vm.dirty_writeback_centisecs = {50-100}
> The performance limitation which is helped by tuning the VM to push
> dirty pages earlier is in NFS not the underlying filesystem, so this
> technique is useful with XFS too.

Hmmm. I'll have to look into that. I'm running an NFS server on a  
NSLU2 "slug" and it needs all the help it can get.

Thanks for the info.

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