[CentOS] more software raid questions

Wed Oct 20 13:59:03 UTC 2010
Rudi Ahlers <Rudi at SoftDux.com>

On Wed, Oct 20, 2010 at 4:34 AM, Nataraj <incoming-centos at rjl.com> wrote:
> When I create my Raid arrays, I always use the option --bitmap=internal.
> With this option set, a bitmap is used to keep track of which pages on
> the drive are out of date and then you only resync pages which need
> updating instead of recopying the whole drive when this happens. In the
> past I once added a bitmap to an existing raid1 array using something
> like this. This may not be the exact command, but I know it can be done:
> mdadm /dev/mdN --bitmap=internal
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How do you add  --bitmap=internal to an existing, running RAID set? I
have tried with the command above but got the following error:

[root at intranet ~]# mdadm /dev/md2 --bitmap=internal
mdadm: -b cannot have any extra immediately after it, sorry.
[root at intranet ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 hda1[0]
      104320 blocks [2/1] [U_]

md2 : active raid1 sda1[0] sdb1[1]
      244195904 blocks [2/2] [UU]

md1 : active raid1 hda2[0]
      244091520 blocks [2/1] [U_]

Kind Regards
Rudi Ahlers

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