This is exactly the idea I suggested the other day... I hope it meets with
everone's approval! it also could be used to force the system to move
data off a SPARE disk if I want to keep the same disk spare unless it's
being used.... for neatness....
I realise that it leaves an inconsistant filesystem, but that's OK in some
applications.... Also, it depends on the filesystem in use to some
degree....
Comments?
On Mon, 29 Mar 1999, Harald Hoyer wrote:
> Hi,
>
> I made a small kernel and raidtools patch to mark a specific device as dirty
> (failure).
>
> Suppose you have as a /etc/raidtab
> raiddev /dev/md4
> chunk-size 128
> raid-level 1
> nr-raid-disks 2
> nr-spare-disks 1
> device /dev/loop1
> raid-disk 0
> device /dev/loop2
> raid-disk 1
> device /dev/loop3
> spare-disk 0
>
> So you have a mirror with 2 devices and one spare disk. Now you create the raid
> device. Set up a file system, etc.
>
> Suddenly you want to backup the mirror with no downtime, so you do a
>
> raidmarkdirty /dev/md4 /dev/loop2
> raidhotremove /dev/md4 /dev/loop2
>
> Now you can mount /dev/loop2 and backup it, while /dev/loop3 is updated.
>
> After /dev/loop3 is in sync, we can play the same game:
>
> raidhotadd /dev/md4 /dev/loop2
> raidmarkdirty /dev/md4 /dev/loop3
> raidhotremove /dev/md4 /dev/loop3
>
> Now you can mount /dev/loop3 and backup it, while /dev/loop2 is updated.
>
> Got the thing ??
>
> OK ..... if you like it, test and improve it :) Please answer me directly, as
> I am not on the raid mailing list.
>
> So long,
> Harald
>
> --
> � Harald Hoyer ���� mailto:[EMAIL PROTECTED] ���� http://hot.spotline.de ��
> �������������������������������������������������������������������������������
> COMPASS [for the CDC-6000 series] is the sort of assembler one expects from
> a corporation whose president codes in octal.
> -- J.N. Gray
>
James ([EMAIL PROTECTED])
It doesn't run on an open source platform,
therefore it, by definition, does not matter.
