Alan Chandler wrote: > Bob Proulx wrote: > >I am wondering if you are running into the fsync() debacle? > > Might be. Because this is my desktop which powers down at night I > have to use anacron to run my daily backup. This rsyncs my virtual > machine images (about 70GB of them) to another machine as backup and > seems to be faily heavy on disk usage for a few hours each morning. > That is when I get the worst experience - reading slashdot before I > start the day. 70G would be much larger than any expected buffer cache. I would expect that would thrash your file buffer cache completely. Are the contents of the images changing daily? This might be interesting reading concerning this issue. Patches to rsync and benchmarks of it using posix_fadvise() with POSIX_FADV_DONTNEED and POSIX_FADV_NOREUSE flags to avoid file buffer cache thrash. http://lwn.net/Articles/449420/ Or you could simply move the start of the backup earlier so as to finish before you get to slashdot in the morning. :-) That is probably what I would do. Bob
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