Hey, Bob - It might be worth exploring where your data stream for the writes was coming from. Moreover, it might be worth exploring how fast it was filling up caches for writing.
Were you delivering enough data to keep the disks busy 100% of the time? I have been tricked by this before... :) Nathan. On Tue, 2006-08-15 at 01:38, James C. McPherson wrote: > Bob Evans wrote: > > Just getting my feet wet with zfs. I set up a test system (Sunblade > > 1000, dual channel scsi card, disk array with 14x18GB 15K RPM SCSI > > disks) and was trying to write a large file (10 GB) to the array to > > see how it performed. I configured the raid using raidz. > > > > During the write, I saw the disk access lights come on, but I noticed > > a peculiar behavior. The system would write to the disk, but then > > pause for a few seconds, then contineu, then pause for a few seconds. > > > > > > I saw the same behavior when I made a smaller raidz using 4x36 GB > > scsi drives in a different enclosure. > > > > Since I'm new to zfs, and realize that I'm probably missing > > something, I was hoping somebody might help shed some light on my > > problem. > > Hi Bob, > I'm pretty sure that's not a problem that you're seeing, just > ZFS' normal behaviour. Writes are coalesced as much as possible, > so the "pauses" that you observed are most likely going to be > the system waiting for suitable IOs to be gathered up and sent > out to your storage. > > If you want to examine this a bit more then might I suggest the > DTrace Toolkit's iosnoop utility. > > > best regards, > James C. McPherson > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss -- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
