How to interpret iozone values

Posted by Henno on Server Fault See other posts from Server Fault or by Henno
Published on 2011-02-13T13:11:58Z Indexed on 2011/02/13 15:27 UTC
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linux

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iops

I ran a test to measure my I/O IOPS on Linux:

iozone -s 4g -r 2k -r 4k -r 8k -r 16k -r 32k -O -b /tmp/results.xls

iozone claims that output is in operations per second yet the numbers are too big for that to be plausible. I'm observing some 320 CMDs/s maximum on vmware esx console (esxtop, then v).

    File size set to 4194304 KB
    Record Size 2 KB
    Record Size 4 KB
    Record Size 8 KB
    Record Size 16 KB
    Record Size 32 KB
    OPS Mode. Output is in operations per second.
    Command line used: iozone -s 4g -r 2k -r 4k -r 8k -r 16k -r 32k -O -b tmpresults.xls
    Time Resolution = 0.000001 seconds.
    Processor cache size set to 1024 Kbytes.
    Processor cache line size set to 32 bytes.
    File stride size set to 17 * record size.
                                                        random  random    bkwd   record   stride
          KB  reclen   write rewrite    read    reread    read   write    read  rewrite     read   fwrite frewrite   fread  freread
     4194304       2   19025    5580    27581    29848     284     198     415  1103217     1498    18541     4340   24245    25618
     4194304       4   15650   21942    18962    21068     252    1198     193   976164     1677    22802    23093   21089    21232
     4194304       8   11121   11638    10273    10165     247    1196     202   625020^C

The test ran for 15 hours before I pressed ^C. Is that ordinary expectation for such command line (dedicated 4 drive RAID10 LUN, 10k RPM SAS drives in EMC CX300)?

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