On Wed, 2013-06-12 at 06:34 -0400, Ric Wheeler wrote: > On 06/12/2013 04:26 AM, Roger Oberholtzer wrote: > > On Tue, 2013-06-11 at 11:12 -0500, Steve Bergman wrote: > >> Are you saying that with XFS there is no periodic > >> flushing mechanism at all? And that unless there's an > >> fsync/fdatasync/sync or the memory needs to be reclaimed, that it can > >> sit in the page cache forever? > > I read the later responses to this and they seemed to say that the data > > in the page cache should be written to the disk periodically. I am not > > meaning to hijack the thread. I just have a question directly related to > > this point. > > You most likely need to adjust some of the vm tunings to cause the vm to kick > out pages more evenly. Not sure what the opensuse crowd would suggest tweaking. In progress. > > I have an application that is streaming data to an XFS disk at a > > sustained 25 MB/sec. This is well below what the hardware supports. The > > application does fopen/fwrite/fclose (no active flushing or syncing). > > Sounds like this is more likely to be an application issue than a file system > one. Can you push the IO write speed up with a simple "dd" test to a file? I have a small test app that can either write at full speed (100 MB/Sec as it turns out on the system in question) or at the app rate of 25 MB/Sec. When at full speed, the cache becomes bigger faster. But the result is the same. Memory eventually seems to be all taken by the cache. It is freed when I umount the file system or "echo 1 > /proc/sys/vm/drop_caches" Yours sincerely, Roger Oberholtzer Ramböll RST / Systems Office: Int +46 10-615 60 20 Mobile: Int +46 70-815 1696 roger.oberholtzer@xxxxxxxxxx ________________________________________ Ramböll Sverige AB Krukmakargatan 21 P.O. Box 17009 SE-104 62 Stockholm, Sweden www.rambollrst.se _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
