Topic
  • 4 replies
  • Latest Post - ‏2012-06-08T15:33:04Z by Peter.yang
Peter.yang
Peter.yang
3 Posts

Pinned topic AIX7 connected other factory storage using iscsi protocol,but very slow!

‏2012-06-06T16:21:15Z |
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.
Updated on 2012-06-08T15:33:04Z at 2012-06-08T15:33:04Z by Peter.yang
  • Peter.yang
    Peter.yang
    3 Posts

    Re: AIX7 connected other factory storage using iscsi protocol,but very slow!

    ‏2012-06-07T09:57:47Z  
    when iostat,the iowait is 22%~31%

    I want to open big frame.
    mtu=9000
    tcp_nagle_limit=0
  • mmveiga
    mmveiga
    78 Posts

    Re: AIX7 connected other factory storage using iscsi protocol,but very slow!

    ‏2012-06-07T14:23:27Z  
    when iostat,the iowait is 22%~31%

    I want to open big frame.
    mtu=9000
    tcp_nagle_limit=0
    Hi 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.

    Regards,
    Marcelo.
  • mmveiga
    mmveiga
    78 Posts

    Re: AIX7 connected other factory storage using iscsi protocol,but very slow!

    ‏2012-06-07T14:42:13Z  
    • mmveiga
    • ‏2012-06-07T14:23:27Z
    Hi 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.

    Regards,
    Marcelo.
    Sorry, we also set rfc1323 to 1 in the interface ...

    Marcelo.
  • Peter.yang
    Peter.yang
    3 Posts

    Re: AIX7 connected other factory storage using iscsi protocol,but very slow!

    ‏2012-06-08T15:33:04Z  
    • mmveiga
    • ‏2012-06-07T14:42:13Z
    Sorry, we also set rfc1323 to 1 in the interface ...

    Marcelo.
    Thanks 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.?

    why?

    3.cp /local/xx /storage/xx, the speed is very lowly,about 15m/s