reducing I/O and system load

Matt McCutchen hashproduct at verizon.net
Fri Feb 17 01:42:25 GMT 2006


On Thu, 2006-02-16 at 15:58 -0800, Philip Lowman wrote:
> On Thu, Feb 16, 2006 at 07:49:03PM +0800, Denis Solovyov wrote:
> > I'm using rsync for simple daily back up data from one HD to another. It
> > takes  about  10  minutes  daily  under  "nice  -n  19".  The problem is
> > well-known  as  I  see  -  several other services such as httpd or mysql
> > begin responding slowly  (up  to  10 sec for mysql queries which usually
> > processed in a small fraction of a second).
>      --bwlimit=KBPS          limit I/O bandwidth; KBytes per second

--bwlimit only limits the rate of transfer over the network.  Vilius
Puidokas encountered the same problem and traced it to the scanning as
rsync generates the file list.  He wrote a patch that adds a --slow-down
option that makes rsync wait a few microseconds in between scanning each
file.  Find it here:
	http://vilius.multiply.com/video/item/10

-- 
Matt McCutchen
hashproduct at verizon.net
http://hashproduct.metaesthetics.net/



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