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On one of our server Hardware RAID1(mirroring) is configured. Now we need to break the RAID1 and simply use the other Hard disk separated from RAID to extend the LVM on that server.

Can some one tell me what will be outcome of this action. Because I have not done this before although this is test server but still I want to be careful.

If needed extra information I will add to Question.

df -h output

Filesystem            Size  Used Avail Use% Mounted on
                       48G  3.4G   42G   8% /
                       49G  4.2G   42G  10% /home
                      190G  122G   58G  68% /u001
                       99M   12M   82M  13% /boot
tmpfs                 2.0G     0  2.0G   0% /dev/shm
/dev/sdc1             230G  173G   46G  80% /mnt

We will add extra space to LVM LogVol01

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It would help to know your model of hardware raid controller. For future reference, this kind of stuff tends to be easier with software raid. – Gilles Feb 13 '13 at 22:58
Please give information on how you manage existing RAID ? Is it a real hardware RAID or type of software/fake RAID using it via mdadm ? – domi27 Feb 14 '13 at 7:59
Actually this is REAL Hardware RAID. And is a Tayan server – OmiPenguin Feb 14 '13 at 12:31

That's a fakeraid managed with the dmraid package, which is why it shows up in /dev/mapper. I suggest backing up the system and blowing away the fake raid array with the bios utility. This may leave you with two identical disks, or may leave them both unusable ( hence, the backup ). Whether you have to restore or not, you can then add the second disk to LVM:

pvcreate /dev/sdb
vgextend VolGroup00 /dev/sdb
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Plus I'd recommend never use FakeRaids and prefer Linux Software RAID (aka MD) instead – poige Dec 15 '13 at 16:03
@poige, well the question was how to not use raid at all, so... – psusi Dec 15 '13 at 18:37

I have done it, but never faced a problem. All the data on the server was there like it was on RAID1. I have heard that some people have experienced some difficulties when doing it. You might lose data, but that's kinda 1 of 100 break's. I suggest doing a backup before breaking the RAID, its just a fail safe for you so your data is still there.

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Can you please recall how you did it. It will be really helpful for me. Thanks – OmiPenguin Feb 14 '13 at 7:46

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