> Would running two CP command to copy 2 different set of files to two > different targets suffice as a basic two thread test? > So long as you generate disk access through a file system and not hdparm. > Is there a way to monitor actual disk transfers from command line without > having to do manual timing? Like I said: iostat iostat -m 1 iostat -x 1 iostat -d 1 iostat -xm 1 Choose whatever information/data you fancy. In fact, let me just post some iostat output to settle this once and for all. I shall risk the annoyance of all by attaching the output of a 'iostat -m sda sdb md1 1' command. This was generated by a single Linux client connected via cifs do a cp -r off the cifs remote share to local disk. The output was generated on the remote share box. From the output, I guess one loses grounds for claiming that md raid1 only reads off one disk even if there are periods of time when it really does only read off one disk. -------------- next part -------------- A non-text attachment was scrubbed... Name: md_does_multipath.bz2 Type: application/x-bzip Size: 2558 bytes Desc: not available URL: <http://lists.centos.org/pipermail/centos/attachments/20090221/22102ba0/attachment-0004.bin>