Fwd: Re: Device utilization with RAID-1

hi,

I didn't want to complain in general about SW RAID-1 performance. I
simply think something is wrong with my setup and I have currently no
idea how to improve.

The basic questions (where I did not find an answer, neither in FAQ's
nor in forum discussions) are.
a) Is it normal that the hard drives show an permanent utilization
(around 20%) without any noticeable actions on the computer?
b) Should (as long as no resync happens) the state of mdadm active or clean?

cheers,
  harald

well, I have only 2 hard drives and no space for more..

Am 16.08.2011 03:29, schrieb Roberto Spadim:

try raid10 far layout

2011/8/15 Harald Nikolisin <hochglanz@gmail.com
<mailto:hochglanz@gmail.com>>

    Since a long time I'm unhappy with the performance of my RAID-1 system.
    Investigation with atop and iostat unveils that the disk utilization is
    always on a certain level although nothing happens on the system. In the
    case of reading or writing files the utilization boosts always to 100%
    for a long time. Very ugly examples are "Firefox starting" or "zypper
    updates".
    That is snapshot of the output of iostat:


    Device:         rrqm/s   wrqm/s     r/s     w/s   rsec/s   wsec/s
    avgrq-sz avgqu-sz   await  svctm  %util
    sda               0,00     0,00    0,00    7,33     0,00    43,33
    5,91     0,33   43,18  33,32  24,43
    sdb               0,00     0,00    0,00    7,33     0,00    43,33
    5,91     0,35   45,59  39,73  29,13
    md0               0,00     0,00    0,00    0,67     0,00     5,33
    8,00     0,00    0,00   0,00   0,00
    md1               0,00     0,00    0,00    0,33     0,00     5,33
    16,00     0,00    0,00   0,00   0,00
    md2               0,00     0,00    0,00    0,33     0,00     1,00
    3,00     0,00    0,00   0,00   0,00
    md3               0,00     0,00    0,00    0,00     0,00     0,00
    0,00     0,00    0,00   0,00   0,00
    md4               0,00     0,00    0,00    0,00     0,00     0,00
    0,00     0,00    0,00   0,00   0,00
    md5               0,00     0,00    0,00    0,33     0,00     0,67
    2,00     0,00    0,00   0,00   0,00

    I checked with mdadm if a resync happens or so, but this is not the
    case. The state says "active" on all RAID devices - btw. what is the
    difference to "clean" ?

    thanks for any hints,
     harald
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-- 
Roberto Spadim
Spadim Technology / SPAEmpresarial