Linked by Thom Holwerda on Tue 10th Mar 2009 15:05 UTC, submitted by vijayd81
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RE[4]: filesystem performance with LVM?
by giddie on Thu 12th Mar 2009 15:02
in reply to "RE[3]: filesystem performance with LVM?"
Turning barriers off at the filesystem level will certainly improve performance. However, if barriers are enabled for a filesystem on an LVM device, you'll get the overhead of using barriers in the filesystem code (I believe), but those barriers won't be honoured by LVM.
If this is the case, when using LVM it makes sense to disable barriers on the filesystems in question, as they're not horoured and will decrease performance.




Member since:
2009-03-11
My recollection was wrong -- it seems that when barriers are turned off, Linux filesystems act unsafely instead of simulating barriers with flushes and waits. So the lack of barriers actually improves performance.