p550 setup aix7, storage created raid5 with 6 disks,using iscsi protocol,
I connected storage with 1000mbps switch,in my win7 notebook , I copy a file to storage,speed about 80M/s, when p550 connected storage, I dd a file frome localdisk to storage:
time dd if=/test/cache-2010.2.8.1104-ppc64.tar of=/backup/peter/cache-2010.2.8.1104-ppc64.tar bs=1024
the speed is about 30M/s, why the speed reduce great?
I find same help,maybe queue_depth or other reasons.
thanks for your help.
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4 replies Latest Post - 2012-06-08T15:33:04Z by Peter.yang
Pinned topic AIX7 connected other factory storage using iscsi protocol,but very slow!
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Updated on 2012-06-08T15:33:04Z at 2012-06-08T15:33:04Z by Peter.yang
Re: AIX7 connected other factory storage using iscsi protocol,but very slow!2012-06-07T09:57:47Z in response to Peter.yangwhen iostat,the iowait is 22%~31%
I want to open big frame.
mmveiga 270003EPEE78 PostsACCEPTED ANSWER
Re: AIX7 connected other factory storage using iscsi protocol,but very slow!2012-06-07T14:23:27Z in response to Peter.yangHi Peter.
I don't have a lot of experience with iSCSI storage, only recently I started to work with it.
In my setup we always increase the queue_depth to 128 in the LPARs and in the backing device from the VIO server.We also increase tcp_recvspace and tcp_sendspace to 262144 (256K) for the TCP/IP interface.
The queue_depth was recommended by the storage vendor and we performed a couple of tests with dd command to confirm that was optimal. We used iostat -RDTL to get the extended disk statics, including the information on queued I/O.
Hope this information helps.
mmveiga 270003EPEE78 Posts
Re: AIX7 connected other factory storage using iscsi protocol,but very slow!2012-06-08T15:33:04Z in response to mmveigaThanks mmveiga.
today I had test
1,modify Hdisk queue_depth=18 (bacause my array has 6 disks),the performace had not improve,just up about 3~5m/s
2,dd with parameter "count=2" ,time dd if=/local/xx of=/storage/xxx bs=1m count=2
the time is about 8s, so thte speed is about 480/8=60m/s,the speed neary in Windows platform
? I haven't test count=4,6,8..,
I test count=20,but the speed is thesome as count=1.?
3.cp /local/xx /storage/xx, the speed is very lowly,about 15m/s