On Wed, 26 Mar 2008, Neelakanth Nadgir wrote: > When you experience the pause at the application level, > do you see an increase in writes to disk? This might the > regular syncing of the transaction group to disk.
If I use 'zpool iostat' with a one second interval what I see is two or three samples with no write I/O at all followed by a huge write of 100 to 312MB/second. Writes claimed to be a lower rate are split across two sample intervale. It seems that writes are being cached and then issued all at once. This behavior assumes that the file may be written multiple times so a delayed write is more efficient. If I run a script like while true do sync done then the write data rate is much more consistent (at about 66MB/second) and the program does not stall. Of course this is not very efficient. Are the 'zpool iostat' statistics accurate? Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
