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uneven Drive Utilization in Copy Phase.

Question asked by jerdavis2 on Jan 12, 2015
Latest reply on Jan 26, 2015 by jerdavis2
I notice that often during the copy phase, I get uneven drive utilization. This workload has a large enough volume of data, and large enough number of keys, that it should otherwise fully distribute. I have a very evenly distributed 70% free disk space across the cluster, and the nodes are all homogeneous. However I often see idle disks.
This shows 2 pools of 3 disks that are fully utilized but the other disks/pools are not touched, and is typical across the cluster.
MapR 3.1.0.

    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
               1.01   47.09    1.94    2.56    0.00   47.40
    
    Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
    sdb               0.80     0.80  102.80   48.60 12118.40 21220.80   440.41    65.76  415.34   6.61 100.00
    sdd               0.20     0.00  104.40   42.80 13137.60 18400.00   428.50    68.61  450.92   6.79 100.00
    sdg               0.40     0.00   71.60    0.00 10377.60     0.00   289.88     3.35   48.00  11.90  85.22
    sdc               0.60     1.00  107.80   49.00 12750.40 20684.80   426.47    59.82  402.64   6.38 100.00
    sdf               0.20     0.00   78.00    0.00 12912.00     0.00   331.08     4.19   55.20  11.91  92.88
    sdi               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
    sdh               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
    sdj               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
    sdk               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
    sdl               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
    sde               0.00     0.00   71.80    0.00 11812.80     0.00   329.05     3.34   46.65  12.19  87.50
    sdm               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00

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