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i'am having IBM server with Redhat 5 ElsmP connected to the IBM Storage over iSCSI (in sdb ) can someone explain this output from iostat command 

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          12.79    0.01    4.53   72.22    0.00   10.45

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda              95.63        48.88       240.95  485589164 2393706728
sdb              29.20       350.49       402.08 3481983365 3994494696

move large file to sdb very slowly,it seem normaly?

Kyle Brandt
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dani.jtk
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2 Answers2

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The following articles will give you a better idea about iostat. I always use iostat -x .

http://mituzas.lt/2009/03/11/iostat/

http://www.igvita.com/2009/06/23/measuring-optimizing-io-performance/

nitins
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  • Good example why "read the docs" is rarely an acceptable answer. Very little explained in those links. For example: What is TPS? – DraxDomax May 05 '16 at 14:52
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It appears you have 72.22% iowait(time spent by a process while waiting for disk I/O to complete) which is likely why the file move is slow.

gekkz
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  • sdb mounted to IBM external Storage over iscsi and we have cronjob to move file from sda to sdb – dani.jtk Mar 12 '10 at 18:25
  • You need to look at the IBM external storage stats. That's where the bottleneck appears to be. – xenny Mar 26 '10 at 15:25