Re: how to resetup fake-raid
On Fri, Nov 12, 2010 at 10:58 PM, Mike Viau <viaum@sheridanc.on.ca> wrote:
>> On Fri, 12 Nov 2010 19:48:48 -0500 <tomh0665@gmail.com> wrote:
>> >>On Fri, Nov 12, 2010 at 7:13 PM, Mike V. wrote:
>> >> Date: Thu, 11 Nov 2010 08:10:55 -0500
>> >>
>> >> I am trying to re-setup my fake-raid (RAID1) volume with LVM2 like setup
>> >> previously. I had been using dmraid on a Lenny installation which gave me
>> >> (from memory) a block device like /dev/mapper/isw_xxxxxxxxxxx_ and also
>> >> a /dev/OneTB-RAID1, but have discovered that the mdadm has replaced
>> >> the older and believed to be obsolete dmraid for multiple disk/raid support.
>> >>
>> >> Automatically the fake-raid LVM physical volume does not seem to be set up.
>> >> I believe my data is safe as I can insert a knoppix live-cd in the system and
>> >> mount the fake-raid volume (and browse the files). I am planning on perhaps
>> >> purchasing another at least 1TB drive to backup the data before trying too
>> >> much fancy stuff with mdadm in fear of loosing the data.
>> >>
>> >> pvdisplay (showing the /dev/md/[device] not recognized yet by LVM2)
>> >> --- Physical volume ---
>> >> PV Name /dev/sdc7
>> >> VG Name XENSTORE-VG
>> >> PV Size 46.56 GiB / not usable 2.00 MiB
>> >> Allocatable yes (but full)
>> >> PE Size 4.00 MiB
>> >> Total PE 11920
>> >> Free PE 0
>> >> Allocated PE 11920
>> >> PV UUID wRa8xM-lcGZ-GwLX-F6bA-YiCj-c9e1-eMpPdL
>> >>
>> >> cat /proc/mdstat
>> >> Personalities :
>> >> md127 : inactive sda[1](S) sdb[0](S)
>> >> 4514 blocks super external:imsm
>> >>
>> >> ls -l /dev/md/imsm0
>> >> lrwxrwxrwx 1 root root 8 Nov 7 08:07 /dev/md/imsm0 -> ../md127
>> >>
>> >> ls -l /dev/md127
>> >> brw-rw---- 1 root disk 9, 127 Nov 7 08:07 /dev/md127
>> >>
>> >> update-initramfs -u
>> >> update-initramfs: Generating /boot/initrd.img-2.6.32-5-xen-amd64
>> >> mdadm: cannot open /dev/md/OneTB-RAID1-PV: No such file or directory
>> >
>> > So it looks like I can not even access the md device the system created on
>> > boot. Does anyone have a guide or tips to migrating from the older dmraid
>> > to mdadm for fake-raid?
>> >
>> > fdisk -uc /dev/md127
>> > Unable to read /dev/md127
>> >
>> > dmesg
>> > [ 4.214092] device-mapper: uevent: version 1.0.3
>> > [ 4.214495] device-mapper: ioctl: 4.15.0-ioctl (2009-04-01) initialised: dm-devel@redhat.com
>> > [ 5.509386] udev[446]: starting version 163
>> > [ 7.181418] md: md127 stopped.
>> > [ 7.183088] md: bind
>> > [ 7.183179] md: bind
>>
>> No necessarily being helpful but thought that I'd point out that
>> "pvdisplay" shows "/dev/sdc7" not "/dev/md127" and "cat /proc/mdstat"
>> shows both sda and sdb as spares...
>>
>> I'd ask on the mdraid list if I were you, especially since mdraid
>> replacing dmraid must be a recent change.
>
> Thanks for the feedback. The physical logical volume on /dev/sdc7 actually not part of the
> fake-raid that I am trying to setup again, but /dev/sd[ab] certain are.
>
> I assume the '(S)' denoted them are spares? Do you know if there is any way to 'activate'
> them both for use like in 'activating' a LVM volume group?
>
> I noticed there is a Linux raid mailing list at: http://vger.kernel.org/vger-lists.html#linux-raid
> Is this the mailing list you were referring too? It seems like a devel list with patch submissions
> and stuff by looking at the archives.
You're welcome.
Yes, I was pointing out that LVM was seeing just sdc7 as a PV of XENSTORE-VG.
Yes, '(S)' = spare, which means that mdraid doesn't think that there's
any data on sda and sdb so activation isn't an option.
Yes, that's the list to which I was referring. It's for users too.
Reply to: