On Friday December 2, eyal@xxxxxxxxxxxxxx wrote:
> Neil Brown wrote:
> >>Q1) What is the correct command to bring these three up as
> >> degraded?
> >
> >
> > mdadm --assemble --force /dev/mdX /dev/sd[abc]1
> >
> > However this won't work with the superblocks you have. So
> >
> > mdadm --create /dev/mdX -l5 -c256 -n4 missing /dev/sda /dev/sdb /dev/sdc
>
> I do not see 'missing' the the mdadm manpage, but maybe Debian is too
> far behind?
It is in the section on "CREATE MODE"
To create a "degraded" array in which some devices are missing, simply
give the word "missing" in place of a device name. This will cause
mdadm to leave the corresponding slot in the array empty. For a RAID4
or RAID5 array at most one slot can be "missing"; for a RAID6 array at
most two slots. For a RAID1 array, only one real device needs to be
given. All of the others can be "missing".
>
> # mdadm --version
> mdadm - v1.9.0 - 04 February 2005
The section I quoted is from the man page for 1.12.0, but that text
certainly predates 1.9.0.
>
> Should I use 2.1 (is it safe to upgrade to it)?
You don't need to, but you can. It is safe to upgrade.
>
> I built it anyway and I do not see 'missing' listed in
> mdadm --create --help
I do.
$ /sbin/mdadm --create --help
Usage: mdadm --create device -chunk=X --level=Y --raid-devices=Z devices
This usage will initialise a new md array, associate some
devices with it, and activate the array. In order to create an
array with some devices missing, use the special word 'missing' in
^^^^^^^
place of the relevant device name.
>
> Reading the new mdadm.man I can see what .missing' does, good.
>
> I got it up (fsck now running), thanks a lot.
Good to hear.
NeilBrown
>
> --
> Eyal Lebedinsky (eyal@xxxxxxxxxxxxxx) <http://samba.org/eyal/>
> attach .zip as .dat
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