On Wed, Dec 16, 2009 at 7:41 AM, Edward Ned Harvey <sola...@nedharvey.com> wrote: > I'll first suggest questioning the measurement of speed you're getting, > 12.5Mb/sec. I'll suggest another, more accurate method: > date ; zfs send somefilesystem | pv -b | ssh somehost "zfs receive foo" ; > date
The send failed (I toggled com.sun:auto-snapshot on the new fs so snapshots would continue running elsewhere), but the summary line reads: summary: 760 GByte in 18 h 35 min 11.6 MB/s, 9x empty > speed. You'll stop seeing the "burstiness" caused by buffering, and > actually see the speed of whatever is the bottleneck. 60 second intervals on iostat provided enough smoothing, it would appear. > Assuming you're on GB ether ... You said 12.5 MB/s, which is coincidentally > exactly 100Mb/sec. But assuming you're tunneling over ssh, then the actual I'm sending to another fs in the same pool to enable dedup. No network involved. > Also, you're reading from raidz2? Or you're writing to raidz2? Same zpool, raidz2. > Raidz2 is not exactly the fastest configuration in the world. You might try > doing a "zfs send" to /dev/null and see how fast the disks themselves > actually go. I'm running it right now through mbuffer, since that gives a speed estimate. It's well above 250 MB/s. Maybe I should have said that zfs receive is slow, since that appears to be the case. I noticed the same issue on another host, but assumed that was because it has a slow CPU and less RAM (Atom 330, 2GB). It was doing a receive at about the same speed to a 2 disk non-redundant pool over gigabit. > If you want better performance, think about using a bunch of mirrors, and > concatenating (striping) them together. You'll have better performance but > less usable space that way. I don't need the performance for normal use. Space and MTTDL were my priorities. -B -- Brandon High : bh...@freaks.com Better to understand a little than to misunderstand a lot. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
