Date: Thu, 06 Nov 2008 16:09:43 +1000 From: Danny Carroll <danny@dannysplace.net> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-hardware@freebsd.org Subject: Re: Areca vs. ZFS performance testing. Message-ID: <49128A27.2080405@dannysplace.net> In-Reply-To: <geru8q$fbr$1@ger.gmane.org> References: <490A782F.9060406@dannysplace.net> <geesig$9gg$1@ger.gmane.org> <490FE404.2000308@dannysplace.net> <geru8q$fbr$1@ger.gmane.org>
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Ivan Voras wrote: > Danny Carroll wrote: > >> - I have seen sustained 130Mb reads from ZFS: >> capacity operations bandwidth >> pool used avail read write read write >> ---------- ----- ----- ----- ----- ----- ----- >> bigarray 1.29T 3.25T 1.10K 0 140M 0 >> bigarray 1.29T 3.25T 1.00K 0 128M 0 >> bigarray 1.29T 3.25T 945 0 118M 0 >> bigarray 1.29T 3.25T 1.05K 0 135M 0 >> bigarray 1.29T 3.25T 1.01K 0 129M 0 >> bigarray 1.29T 3.25T 994 0 124M 0 >> >> ad4 ad6 ad8 cpu >> KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id >> 0.00 0 0.00 65.90 375 24.10 63.74 387 24.08 0 0 19 2 78 >> 0.00 0 0.00 66.36 357 23.16 63.93 370 23.11 0 0 23 2 75 >> 16.00 0 0.00 64.84 387 24.51 63.79 389 24.20 0 0 23 2 75 >> 16.00 2 0.03 68.09 407 27.04 64.98 409 25.98 0 0 28 2 70 > >> I'm curious if the ~130M figure shown above is bandwidth from the array >> or a total of all the drives. In other words, does it include reading >> the parity information? I think it does not since if I look at iostat >> figures and add up all of the drives it is greater than that reported by >> zfs by a factor of 5/4 (100M in Zfs iostat = 5 x 25Mb in standard iostat). > > The numbers make sense - you have 5 drives in RAID-Z and 4/5ths of total > bandwidth is the "real" bandwidth. On the other hand, 25 MB/s is very > slow for modern drives (assuming you're doing sequential read/write > tests). Are you having hardware problems? No, just the IO from disk to net is slow... >> Lastly, The windows client which performed these tests was measuring >> local bandwidth at about 30-50Mb/s. I believe this figure to be >> incorrect (given how much I transferred in X seconds...) > > Using Samba? Search the lists for Samba performance advice - the default > configuration isn't nearly optimal. In my second post I mentioned that the IO windows was reporting was right. I was getting about 50Mb/sec but ZFS was reporting about 130M/s. I timed this by copying 20Gb and timing it with my watch. Just as a rough guide. I am curious about this inconsistency. If anyone has any ideas??? -D
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