Edgar Fuß <ef%math.uni-bonn.de@localhost> writes: > 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? > Do you have physical access to the server during the test? Then you > could have a look whether the discs are really idle (as iostat says) > or busy (as disabling flushing mitigating the problem suggests). I have a WD Elements external USB drive, and it seems to take most of a second to execute a cache flush (via wapbl). It was basically unusable with rdiff-backup (which calls fsync which does a log truncation) with cache flush enabled. The real fix was disabling the fsync in rdiff-backup, but disabling wapbl cache flush ehlped.
Attachment:
pgp4pamqfIMN5.pgp
Description: PGP signature