DL580 raid (dd from linux question)

[Bill McNAMARA_1]

Hi all,

I'm installing a box with RHAS 2.1 on one single disk in a DL580.

I want to be able to dd this disk to a 2 disk raid/striped volume.

Is this an easy task or should I install to two disks to start with?

Thanks,
Bill

[Mark Grant · Accepted solution]

Bill,

Personally I would think that as long as the 2 disk raid/striped volume looked like a single disk of the same size, you might get away with this.

I have to ask why you want to do this though, can't you just install straight onto the raid volume?

[Bill McNAMARA_1]

it's a question of time!
I want to get in and out so to speak!

Thanks,
Bill

[Steven E. Protter]

2 disk raid 1.

That you can do.

2 disk striped.

I don't think so. That requires at least 3 disks.

SEP

[Bill McNAMARA_1]

okay, that makes life easier then..
R1 is possibly what they want to do anyways..

Cheers SEP.

[Don_89]

Install all disks from the start.. This will make your life easier. After the install, do your 'dd'.

BTW, are you doing a hardware or software Raid 1?

[Bill McNAMARA_1]

I used mondorescue which works a treat.

[Mark Travis]

Do not use dd.

It makes bad voodoo happen. I've tried it on RH9 and RHEL3. dd'ing root drives causes severe confusion in the boot loading process.

As in regardless of the device name given to grub/lilo to boot (/dev/hd??), it boots up the original device. And then renames the devices.
/dev/hda1 can become /dev/hdc1 according to df. I don't know why it behaves like this. I've spent over a day on this problem before realizing that I had better things to do. Just use RAID-1 (either hardware or software).

dd'ing root drives in Linux is bad. It makes evil spirits appear. Just don't do it.

[Bill McNAMARA_1]

I do agree with the last point.
If the destination disk is not physically identical (no. cylinders etc..) all is foutu as they say in France.

I used mondorescue which is fantastic if you use lilo and not grub! A tried and tested recommendation for all linux sys admins.

[Bill McNAMARA_1]

mondorescue