Re: Squeeze assembles one RAID array, at boot but not the other
On Mon, 07 Jan 2013 00:14:31 -0700, Bob Proulx wrote:
> Hendrik Boom wrote:
>> I have two RAID arrays on my Debian squeeze system. The old one, which
>> still works, and has worked for years, is on a pair of partitions on two
>> 750GB disks. THe new one is not recognized at boot.
>
> Does at boot time mean at initrd initramfs time?
>
>> boot is *not* on any of these RAIDs; my system boots properly.
>
> Good.
>
>> The new one, whih I build today, resides on similar (but larger)
>> partitions on two 3TB disks. I partitioned these drives today, using
>> gparted for gpt partitioning, then created a RAID1 from two 2.3GB
>> partitions o these disks, set up LVM2 on the RAID drive, created an LVM
>> partition, put an ext4 file system on it and filled it with lots of
>> data. The partition definitely exists.
>>
>> But it is not recognized at boot. The dmesg output tells me all about
>> finding the old RAID, but it doesn't even notice the new one, not even to
>> complain about it.
>
> Did you update /etc/mdadm/mdadm.conf with the new data for the new
> array that you just now built?
no.
>
> See the outout of --detail --scan and edit it into that file.
>
> mdadm --detail --scan
>
> Did you rebuild the initrd images for the booting kernel after having
> done this?
no.
>
> Example:
>
> dpkg-reconfigure linux-image-3.2.0-4-amd64
>
>> Any ideas where to look? Or how to work around the problem?
>
> At one time in the past Debian (and some other distros too) would look
> at the partition type and see 0xFD as an AUTORAID partition and
> automatically mount it. This was reported as a bug because if someone
> were trying to recover a disk problem and attached a random disk to a
> system then at boot time the init scripts would try to automatically
> attach to it. That was undesirable.
>
> Due to that complaint the system was changed so that raid partitions
> must be explicitly specified in the mdadm.conf file. And since for
> the root partition they must be mounted at early boot time this action
> is pushed into the initrd to do so that if the root partition is on
> raid it can be done early enough.
The RAID that's needed at boot time (not for /boot, but for the root
partition is recognised. But it's been around for a long time and
has presumably been pushed into the initrd at every kernel upgrade.
...
...
> In summary:
>
> In Debian after creating a new raid add the new raid info to
> /etc/mdadm/mdadm.conf and then dpkg-reconfigure linux-image-$(uname -r).
will do, and will report back.
>
> In CentOS after creating a new raid edit the grub config and add the
> new rd_MD_UUID values to the grub boot command line. Or use rd_NO_DM.
>
> Bob
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