Add third disk to two disk SOFTWARE raid5?

My problem is as follows:
My old hardware died on me, I replaced it and installed 11.1.
Due to the hardware failure my RAID array that originally existed out
of 3 disks has the third one out of sync, thus effectively reducing it
to a RAID5 with only 2 disks.
As you’ll surely agree… my data isn’t very safe at the moment and I’d
like to add disk #3 to the raid array.

I can’t seem to find any option anywhere in yast to add a disk to an
existing array. I was expecting an “Add” button in the third screenshot
below (The other 2 are just there so hopefully you can get some
information out of it on how to fix it)

‘[image: http://thumbnails9.imagebam.com/2135/41bc0121340688.gif]’
(http://www.imagebam.com/image/41bc0121340688) ‘[image:
http://thumbnails2.imagebam.com/2135/be2b6221340690.gif]’
(http://www.imagebam.com/image/be2b6221340690) ‘[image:
http://thumbnails12.imagebam.com/2135/8a8e5121340693.gif]’
(http://www.imagebam.com/image/8a8e5121340693)


Server: openSUSE 11.0, Athlon 64 3000+, HDD 3 * 1TB, 1*640GB, 1GB RAM,
NV GF2
Desktop: openSUSE 11.1 b5, Intel Q6600, HDD 2 * 320GB, 4GB RAM,
Nvidia 8800GT
Laptop: openSUSE 11.1 b5, Intel p8400, HDD 280GB, 4GB RAM, NVIDIA
9600GT

Axeia’s Profile: http://forums.opensuse.org/member.php?userid=4794
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Hi
What about if you select the device it’s self (sdd) and set it to a
raid file system, can you then add it to the array?

You may wish to investigate the CLI tool mdadm…


Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-4-default
up 1 day 20:40, 2 users, load average: 0.36, 0.28, 0.16
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82

It’s already set to a “OxFD Linux Raid” under the “File system ID” and
that’s pretty much the only I can do with it… no option to add it to an
existing array.


Server: openSUSE 11.0, Athlon 64 3000+, HDD 3 * 1TB, 1*640GB, 1GB RAM,
NV GF2
Desktop: openSUSE 11.1 b5, Intel Q6600, HDD 2 * 320GB, 4GB RAM,
Nvidia 8800GT
Laptop: openSUSE 11.1 b5, Intel p8400, HDD 280GB, 4GB RAM, NVIDIA
9600GT

Axeia’s Profile: http://forums.opensuse.org/member.php?userid=4794
View this thread: http://forums.opensuse.org/showthread.php?t=402407

Axeia;1911985 Wrote:
> RAID array that originally existed out of 3 disks has the third one out
> of sync, thus effectively reducing it to a RAID5 with only 2 disks.
> As you’ll surely agree… my data isn’t very safe at the moment and I’d
> like to add disk #3 to the raid array.
>
A lot of ppl would lose data with 1 disk failure so you were ahead of
the game. But now you’re more than twice as likely to have a failure,
as 2 disks must stay up, and similar models may start failing all
together given similar usage. So you’re right to address it.

RAID5 basically sux…

RAID10 striping mirrored sets, just needs 1 disk more, and offers
higher performance and resilience. You also do 1/2 the Read I/O to fix
the volume.


robopensuse

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I installed “Raid-Monitor” as I stumbled upon it while reading ‘How to
install openSUSE on software RAID - openSUSE’
(http://en.opensuse.org/How_to_install_SUSE_Linux_on_software_RAID)
which seems to make use of the mentioned mdadm.

But it doesn’t give much info… hell the only thing I can get it to do
is display a window with the content below in a textfield.
Code:

Personalities : [raid6] [raid5] [raid4]
md1 : active raid5 sdc1[1] sdb1[3]
1953519616 blocks super 1.0 level 5, 128k chunk, algorithm 0 [3/2] [_UU]
bitmap: 218/466 pages [872KB], 1024KB chunk

unused devices: <none>


Server: openSUSE 11.0, Athlon 64 3000+, HDD 3 * 1TB, 1*640GB, 1GB RAM,
NV GF2
Desktop: openSUSE 11.1 b5, Intel Q6600, HDD 2 * 320GB, 4GB RAM,
Nvidia 8800GT
Laptop: openSUSE 11.1 b5, Intel p8400, HDD 280GB, 4GB RAM, NVIDIA
9600GT

Axeia’s Profile: http://forums.opensuse.org/member.php?userid=4794
View this thread: http://forums.opensuse.org/showthread.php?t=402407

Hi
What about the section called ‘Reconstruction’? Also from the cli use;


man mdadm

This is all the commands and options.

Make sure you have backed up your data as well…!!!


Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-4-default
up 2 days 0:56, 4 users, load average: 0.45, 0.68, 0.78
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82

from what I can tell
Code:

raidhotadd /dev/md1 /dev/sdd

should do the trick, and mdadm can give a lot of information, but I’ve
no idea what to do with it.

So it would be awesome if someone with some expertise in this field
could tell me whether it’s the right command or if I should do something
else… else I guess I’ll just try it out as I got the time now to
restore things if they get messed up.
[edit]:
That’s not it at least :stuck_out_tongue:

Code:

raidhotadd /dev/md1 /dev/sdd1
bash: raidhotadd: command not found


Server: openSUSE 11.0, Athlon 64 3000+, HDD 3 * 1TB, 1*640GB, 1GB RAM,
NV GF2
Desktop: openSUSE 11.1 b5, Intel Q6600, HDD 2 * 320GB, 4GB RAM,
Nvidia 8800GT
Laptop: openSUSE 11.1 b5, Intel p8400, HDD 280GB, 4GB RAM, NVIDIA
9600GT

Axeia’s Profile: http://forums.opensuse.org/member.php?userid=4794
View this thread: http://forums.opensuse.org/showthread.php?t=402407

So I got rather brave and performed the following command:

Code:

mdadm --add /dev/md1 /dev/sdd1

Which instantly replied with “mdadm: re-added /dev/sdd1”.

And now I’m hearing the disks perform some read/write actions while the
computer is idling… so my guess is that it’s working and I’ll just have
to wait till it’s done. I’ll post again when it’s done to let you know
what happened…


Server: openSUSE 11.0, Athlon 64 3000+, HDD 3 * 1TB, 1*640GB, 1GB RAM,
NV GF2
Desktop: openSUSE 11.1 b5, Intel Q6600, HDD 2 * 320GB, 4GB RAM,
Nvidia 8800GT
Laptop: openSUSE 11.1 b5, Intel p8400, HDD 280GB, 4GB RAM, NVIDIA
9600GT

Axeia’s Profile: http://forums.opensuse.org/member.php?userid=4794
View this thread: http://forums.opensuse.org/showthread.php?t=402407

Hi
The following will give you info;


mdadm --detail /dev/md1
and
cat /proc/mdstat


Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 11.1 x86 Kernel 2.6.27.7-4-default
up 2 days 17:57, 2 users, load average: 0.13, 0.22, 0.33
GPU GeForce 6600 TE/6200 TE - Driver Version: 177.82

I installed Raid-Monitor earlier and it’s showing me probably the same
output as that command. At least I know for sure it’s rebuilding.

Code:

Personalities : [raid6] [raid5] [raid4]
md1 : active raid5 sdd1[0] sdc1[1] sdb1[3]
1953519616 blocks super 1.0 level 5, 128k chunk, algorithm 0 [3/2] [_UU]
=======>…] recovery = 36.0% (351710592/976759808) finish=122.4min speed=85040K/sec
bitmap: 133/466 pages [532KB], 1024KB chunk

unused devices: <none>

Takes some time 3 * 1TB :slight_smile:

Thanks for the help and unless I run into trouble… which I don’t
expect to… case closed.


Server: openSUSE 11.0, Athlon 64 3000+, HDD 3 * 1TB, 1*640GB, 1GB RAM,
NV GF2
Desktop: openSUSE 11.1 b5, Intel Q6600, HDD 2 * 320GB, 4GB RAM,
Nvidia 8800GT
Laptop: openSUSE 11.1 b5, Intel p8400, HDD 280GB, 4GB RAM, NVIDIA
9600GT

Axeia’s Profile: http://forums.opensuse.org/member.php?userid=4794
View this thread: http://forums.opensuse.org/showthread.php?t=402407