Add disk to raid1 array in imsm container with mdadm (without losing data). On 82801ER sata raid (ICH5R).

idata — Tue, 22 Dec 2009 23:08:28 GMT

Hi,

imsm = Intel Matrix Storage Manager (called fakeraid by some)

82801ER = Intel chipset sata raid controller

Main question:

I have a imsm container created with mdadm (linux). Inside it is 1 disk (sdb). I also added sdb to a raid1 array with 1 missing disk.

How do I add a new disk (sdc) to the *same* imsm container?

I've tried "mdadm --add /dev/md/imsm /dev/sdc", but this just seems to create a *new* imsm container.

My goal is to recreate imsm raid1 array from 2 new disks after 1 of the original 2 disks failed. The puzzle is to see if this is possible without data loss (so without using the raid bios, because that seems to destroy all data).

Why not just use linux software raid? I want to be able to use the disks in a dualboot configuration from the 'other' OS as well.

Much more details below.

I've searched a lot about this, but could find much information about imsm containers and how to practically use them.

Hope someone with mdadm knowledge and containers and Intel Matrix Storage Manager is able to help.

If there is another way to retain the data on sdb and rebuild the raid1 array (adding sdc), e.g. using windows, I am also interested in the solution.

Greetings,

moon300

More details:

-------------

I'm trying to build an raid1 setup with two 1.5TB disks connected to ICH5R without losing data (just to see if it can be done - all data has been backed up).

Imagine a raid1 on ICH5R where 1 disk has failed, and you want to replace the failed disk. Then the array should rebuild without data loss. How can this be done?

history:

- 2 x 300GB SATA harddisks (A1 and A2) on Intel ICH5R in raid1 (under windows only)

1 disk for OS(es) on IDE (osdisk)

- Disk A2 failed

- Disabled Raid in BIOS (not the 'RAID' BIOS, but the normal BIOS)

- Bought 2 x 1.5TB SATA (B and C) harddisks

- Took failed disk A2 out, Put disk C in

- Installed Linux on osdisk (and left windows on it as well)

- Copied everything from disk A1 to C

- Took disk A1 out

- Put disk B in, then started the quest described below

- sdc = original 'with data', 1st partition mounted as /dwin, 2nd as /dlin

sdb = new = empty

- Create layout on new disk

copy the partition information to the new disk.

sfdisk -d /dev/sdc | sfdisk /dev/sdb

check with fdisk -l

(it has 2 partitions)

- Change partition type on new disk to raid-auto-detect-linux (fd)

fdisk /dev/sdb

t 1 fd

t 2 fd

- Make sure no raid info left from earlier:

mdadm --zero-superblock /dev/sdb1

mdadm --zero-superblock /dev/sdb2

(if there are no remains already you should see "mdadm: Unrecognised md component device - /dev/sdb1")

- Create the container

- mdadm --create /dev/md/imsm --metadata=imsm --raid-disks=2 /dev/sdb1 missing

missing not allowed

Whatever I try: I cannot create the container with a missing disk

- mdadm --create /dev/md/imsm -e imsm --level=container -n 1 --force /dev/sdb

- CREATION OF CONTAINER SUCCEEDED

- mdadm --create /dev/md/myraid --level raid1 -n 2 /dev/sdb missing

- l /dev/md*

imsm -> ../md127 = the container

myraid -> ../md126 = the raid array with 1 missing

/dev/md126

/dev/md126p1

/dev/md126p2

/dev/md127

- cat /proc/mdstat

Personalities : [raid1]

md126 : active raid1 sdb[0]

1465136128 blocks super external:/md127/0 [2/1] [U_]

m1d127 : inactive sdb[0](S)

209 blocks super external:imsm

- fdisk /dev/md126

Device Boot Start End Blocks Id System

/dev/md126p1 1 89238 716800000 fd Linux raid autodetect

/dev/md126p2 89238 182401 748336001 fd Linux raid autodetect

- Create filesystem on new md126

- mkfs.ntfs /dev/md126p1 (slow)

- mkfs.xfs /dev/md126p2

- Mount both partitions and copy all data from sdc to new md126 (is build from 'sdb' and 'missing')

- mount /dev/md126p1 /mnt/win/

- mount /dev/md126p2 /mnt/lin/

- rsync -ax /dwin /mnt/win/

- rsync -ax /dlin /mnt/lin

- Add the sdc disk to the container (first unmount)

- umount /dwin

- umount /dlin

- fdisk /dev/sdc

t 1 fd

t 2 fd

- mdadm --add /dev/md/imsm /dev/sdc

mdadm: added /dev/sdc

- Check

- cat /proc/mdstat

Personalities : [raid1]

md126 : active raid1 sdb[0]

1465136128 blocks super external:/md127/0 [2/1] [U_]

md127 : inactive sdc[1](S) sdb[0](S)

2466 blocks super external:imsm

- Try to add sdc to array

- mdadm --add /dev/md/myraid /dev/sdc

mdadm: Cannot add disks to a 'member' array, perform this operation on the parent container

- mdadm --add /dev/md/myraid /dev/md/imsm

mdadm: Cannot add disks to a 'member' array, perform this operation on the parent container

Looking in the raid bios, I see:

Raid volumes:

ID name level strip size status bootable

0 myraid raid1(mirror) n/a 1397.2GB Rebuild yes

|_samsung HD154UI ...3411 Port0 1397.2GB Normal

Other-RAID disks:

Port Drive Model

1 samsung HD154UI ...3292 1397.2GB Unknown no

So - as expected: sdc is not in the same container.

topic Add disk to raid1 array in imsm container with mdadm (without losing data). On 82801ER sata raid (ICH5R). in Graphics

Add disk to raid1 array in imsm container with mdadm (without losing data). On 82801ER sata raid (ICH5R).