Um...I started 2 commands in 2 separate ssh sessions: in ssh session one: iostat -xn 1 > stats in ssh session two: mkfile 10g testfile
when the mkfile was finished i did the dd command... on the same zpool1 and zfs filesystem..that's it, really On Fri, Jun 18, 2010 at 6:06 AM, Arne Jansen <sensi...@gmx.net> wrote: > Curtis E. Combs Jr. wrote: >> Sure. And hey, maybe I just need some context to know what's "normal" >> IO for the zpool. It just...feels...slow, sometimes. It's hard to >> explain. I attached a log of iostat -xn 1 while doing mkfile 10g >> testfile on the zpool, as well as your dd with the bs set really high. >> When I Ctl-C'ed the dd it said 460M/sec....like I said, maybe I just >> need some context... >> > > These iostats don't match to the creation of any large files. What are > you doing there? Looks more like 512 byte random writes... Are you > generating the load locally or remote? > >> >> On Fri, Jun 18, 2010 at 5:36 AM, Arne Jansen <sensi...@gmx.net> wrote: >>> artiepen wrote: >>>> 40MB/sec is the best that it gets. Really, the average is 5. I see 4, 5, >>>> 2, and 6 almost 10x as many times as I see 40MB/sec. It really only bumps >>>> up to 40 very rarely. >>>> >>>> As far as random vs. sequential. Correct me if I'm wrong, but if I used dd >>>> to make files from /dev/zero, wouldn't that be sequential? I measure with >>>> zpool iostat 2 in another ssh session while making files of various sizes. >>>> >>>> This is a test system. I'm wondering, now, if I should just reconfigure >>>> with maybe 7 disks and add another spare. Seems to be the general >>>> consensus that bigger raid pools = worse performance. I thought the >>>> opposite was true... >>> A quick test on a system with 21 1TB SATA-drives in a single >>> RAIDZ2 group show a performance of about 400MB/s with a >>> single dd, blocksize=1048576. Creating a 10G-file with mkfile >>> takes 25 seconds also. >>> So I'd say basically there is nothing wrong with the zpool >>> configuration. Can you paste some "iostat -xn 1" output while >>> your test is running? >>> >>> --Arne >>> >> >> >> > > -- Curtis E. Combs Jr. System Administrator Associate University of Georgia High Performance Computing Center ceco...@uga.edu Office: (706) 542-0186 Cell: (706) 206-7289 Gmail Chat: psynoph...@gmail.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
