On Sat, Sep 21, 2013 at 11:44:26AM +0200, Edgar Fuß wrote: > ED> 2908 getattr > EF> During which timeframe? > ED> 22.9 seconds. > So that's >100 getattrs per second. > > > Indeed [lots of 549-byte write requests] is weird. > > But how small write could kill WAPBL performances? > No idea. I think I'm out of luck now, but maybe it rings a bell with someone > else. > > It would probably help finding out (with WAPL logging) how often the journal > flushes happen. > > I myself can't make sense out of the combination of > -- vfs.wapbl.flush_disk_cache=0 mitigating the problem > -- neither the RAID set nor its components showing busy in iostat > Maybe during a flush, the discs are not regarded busy?
I suspect that indeed, while a fluch cache command is running, the disk is not considered busy. Only read and write commands are tracked. -- Manuel Bouyer <[email protected]> NetBSD: 26 ans d'experience feront toujours la difference --
