Talk:Convert a single drive system to RAID

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Revision as of 06:53, 15 December 2010 by Carrie (Talk | contribs)

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Note about the "Copy of data" section

While using the rsync command for copying, I had to manually create these files in the new system:

cd /mnt/new-disk/dev
mknod -m 600 console c 5 1
mknod -m 666 null c 1 3
mknod -m 666 zero c 1 5

I thought it should be added, but I don't know wiki code yet, and I'm not sure if the missing files problem applies to every user.

Instructions for Other Distributions

Is there really a need for including Ubuntu instructions? This is the Arch wiki. If we do want to include other distro's, where do we draw the line and which ones to include and which to exclude?

Double Copy

Hi.

Is there a way to avoid double copy ?

I mean, we create a new filesystem and copy all the data to it, then data will be mirrored back to the first drive. Is there a way to avoid one copy, for instance to build a RAID-1 group out of an existing disk. This would be quite faster, wouldn't it ?

As far as I know there is a raid specific block at the end of the disk/partition, maybe we could add it without erasing the rest of the disk ? Probably the existing filesystem has to be reduced no to overwrite later this specific block but for me it sounds possible...

Updated docs

Hi, I recently upgraded an Ubuntu based system from a single rive to RAID-1, and I followed the steps on this page because it was the clearest and best step-by-step documentation that I found on whole net for doing that. I have added some updates because there were a some bits that were unclear to me (e.g. how to use fdisk, had to check the docs for this), and a few problems that I ran into (e.g. the grub setup assumed that the failed disk was still present and that the BIOS settings would not have to be changed, which for me at least was not the case).

These are the steps I applied to my system, and they seemed to work well. However, because I'm using Ubuntu, there were a few bits that were distro-specific, and where these apply I have tried to make these obvious. I'm hoping these parts will still be acceptable on this wiki, because although they are not Arch-linux-specific, the vast majority of the steps (around 95%) are universally applicable to Linux systems, and so it seems the best to have one page with steps, that indicates where differences exist. If this is a problem then please send me a message to let me know, and I'll maintain a copy of this page (still under GFDL of course) with the Ubuntu-specific bits on my separate personal wiki. -- All the best, Nickj 06:46, 22 April 2009 (EDT)

Probably misinformation about grub2+raid1

If you want to use Grub 0.97 (default in the Arch Linux 2010.05 release) on RAID 1, you need to specify an older version of metadata than the default. Add the option "--metadata=0.90" to the above command. Otherwise Grub will respond with "Filesystem type unknown, partition type 0xfd" and refuse to install. This is supposedly not necessary with Grub 2.

But take a look to related document Installing_with_Software_RAID_or_LVM:

If you want to use Grub 0.97 (default in the Arch Linux 2010.05 release) on RAID 1, you need to specify an older version of metadata than the default. Add the option "--metadata=0.90" to the above command. Otherwise Grub will respond with "Filesystem type unknown, partition type 0xfd" and refuse to install. This is necessary also with Grub 2 --Carrie 01:53, 15 December 2010 (EST)