On Tue, 13 Apr 2010 11:23:54 +0200
Keld Simonsen <keld@xxxxxxxxxx> wrote:
> I am not sure it has been said, but for a 4 disk raid10,f2 array
> you should place the first and the second disk on one controller, and then the 3rd
> and 4th on the second controller. Then you would have a copy of all blocks even
> if one controller fails.
Uhmm... no.
Disk: 1 2 3 4
blocks a b c d
e f g h
.........
d a b c
h e f g
If you only have first and second, then block c is missing.
You want 1st and 3rd on one controller, 2nd and 4th on the other
Then either controller can access all blocks.
>
> I believe the order is defined by the order the disks are specified in
> on the mdadm --create line.
Correct.
NeilBrown
>
> best regards
> keld
>
> On Mon, Apr 12, 2010 at 08:26:55PM -0700, Simon Matthews wrote:
> > 2010/4/12 Tomáš Dulík <dulik@xxxxxxxx>:
> > > Stefan /*St0fF*/ Hübner napsal(a):
> > >>
> > >> I cannot quite understand your problem. As every part of the array
> > >> contains it's own metadata, it doesn't matter to md which /dev/sdX a
> > >> drive is. It might matter a bit for boot-time assembly, but actually
> > >> that's what UUIDs are for.
> > >>
> > >
> > > I know how UUIDs work.
> > > My problem with device names is not a "critical", it's about "user
> > > friendliness" of the physical disk management.
> > > If a disk fails and I receive email "A Fail event had been detected on md
> > > device /dev/md2. It could be related to component device /dev/sdd3", how
> > > will I know which disk should be replaced, if the device name is not
> > > fixed/persistent? I
> >
> > Record the serial number of the disks and which bay they are in.
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