Device Question...

Matt Nelson matt at frozenatom.com
Thu Jan 22 13:32:31 MST 2009


So I have had this question on my mind and finally remembered while I was
checking my email to throw this by the PLUG.

Doing a quick iostat:
[root at mythfe1 ~]# iostat -x 5
Linux 2.6.18-92.1.6.el5.centos.plus (mythfe1.xxxxxx.com)     01/22/2009

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           6.88    0.00    1.17    0.48    0.00   91.47

Device:         rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s avgrq-sz
avgqu-sz   await  svctm  %util
sda               0.22     7.32  0.49  2.71    12.70    80.29    29.01
0.02    5.38   1.00   0.32
sdb               6.41     4.25  0.97  0.78    59.06    40.80    57.10
0.01    6.04   2.30   0.40
sdc               6.41     4.24  0.94  0.78    58.83    40.77    58.07
0.01    5.24   2.16   0.37
sdd               6.44     4.25  0.94  0.77    59.04    40.79    58.47
0.01    6.39   2.48   0.42
sde               6.44     4.25  0.91  0.77    58.85    40.77    59.16
0.01    6.22   2.41   0.41
sdf               2.35     2.20  0.29  0.14    21.14    18.97    92.20
0.00   10.44   4.25   0.18
sdg               2.35     2.20  0.29  0.14    21.10    18.96    93.42
0.00    9.46   4.16   0.18
sdh               2.36     2.22  0.28  0.12    21.09    18.96   100.85
0.01   12.85   4.90   0.19
sdi               2.36     2.22  0.28  0.12    21.13    18.97    99.68
0.01   12.97   4.84   0.19
sdj               2.35     2.18  0.29  0.16    21.11    18.97    89.45
0.00    7.86   3.78   0.17
sdk               2.35     2.18  0.29  0.16    21.13    18.97    89.45
0.00    8.36   3.89   0.17
sdl               6.49     4.67  0.86  0.35    58.84    40.76    82.43
0.01    7.93   3.73   0.45
sdm               6.50     4.67  0.88  0.35    59.06    40.79    81.23
0.01    9.16   4.10   0.50
hda               0.69     0.00  0.02  0.00     5.75     0.00   242.79
0.00   15.47  10.48   0.02
md0               0.00     0.00  5.34 24.47   343.89   195.79    18.10
0.00    0.00   0.00   0.00
md1               0.00     0.00  1.86 11.49   122.81    91.94    16.08
0.00    0.00   0.00   0.00
sdn               0.02     5.01  0.10  0.18     7.09    41.54   172.16
0.11  374.60   3.60   0.10


You can see my 14 drives, sda-sdn... My question is this:

What happens when you hit /dev/sdz?  Does it use /dev/sdaa or what?



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