On Sat, 28 Aug 2010 13:09:12 +0400 Ilya Bakulin <webmas...@kibab.com> wrote:
> Right now I'm running phybs -w /dev/ad7p1
Well, phybs finished.
Results:
kibab-desktop# ./phybs -w /dev/ad7p1
count size offset step msec tps kBps
131072 1024 0 4096 3098125 0 42
131072 1024 512 4096 3100047 0 42
65536 2048 0 8192 1505809 0 87
65536 2048 512 8192 1505179 0 87
65536 2048 1024 8192 1506127 0 87
32768 4096 0 16384 1522343 1 86
32768 4096 512 16384 1521017 1 86
32768 4096 1024 16384 1523748 1 86
32768 4096 2048 16384 1522853 1 86
16384 8192 0 32768 890911 3 147
16384 8192 512 32768 892026 3 146
16384 8192 1024 32768 890699 3 147
16384 8192 2048 32768 891862 3 146
16384 8192 4096 32768 889903 3 147
Obviously 34-sectors offset is bad for phybs. Write requests are NEVER get
aligned.
I have recreated partition as follows:
kibab-desktop# gpart delete -i 1 ad7
ad7p1 deleted
kibab-desktop# gpart add -t freebsd-ufs -s 10G -b 63 ad7
ad7p1 added
kibab-desktop# gpart show ad7
=> 34 2930277101 ad7 GPT (1.4T)
34 29 - free - (15K)
63 20971520 1 freebsd-ufs (10G)
20971583 2909305552 - free - (1.4T)
So, we have ad7p1 which is still misaligned, but if write request will start at
offset=512, it will be aligned properly.
Let's test as follows:
kibab-desktop# ./phybs -l 4096 -w /dev/ad7p1
count size offset step msec tps kBps
32768 4096 0 16384 1520609 1 86
32768 4096 512 16384 17898 151 7323
32768 4096 1024 16384 1524899 1 85
:-) Aligned writes are 86 times faster than misaligned!!!
--
Regards,
Ilya Bakulin
http://kibab.com
xmpp://kibab...@jabber.ru
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