In the course of trying to track down some disk performance issues, I'm
trying to mount an XFS partition on a (slow) SCSI disk synchronously via
the fstab entry:
/dev/sda1 /mnt/test xfs logbufs=8,sync 0 0
However, I'm not getting the behavior I would expect:
[root@brian root]# time dd if=/dev/zero of=/mnt/test/bigfile bs=1024k
count=512; time umount /mnt/test
512+0 records in
512+0 records out
So the 'dd' returns after 1 minute, but it takes it another minute to
actually unmount the partition (during which there is lots of writing
going on). I tried adding 'osyncisdysnc', which ISTR is the default now,
and it (obviously) didn't help.
Am I misinterpreting what's going on here? Is this the expected behavoir?
The kernel is 2.4.18 from the 1.1 release.
Department of Biomedical Engineering