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I'm currently running a Raid 0 configuration and wondering if I could switch it to a Raid 1 config without losing any data currently on the 2 drives. Is there any software that will allow it to happen? Do I have to create a complete image of the raid 0; reconfigure and re-format and then restore the image? I currently have 2, 640 gig drives running Raid 0. About 300 gig is currently stored on the array. Would the back-up image be 300 gig or 1.2 terrabytes.

Thanks.

  • Need more details about OS, RAID controller (hardware or software), etc. – Kevin Kuphal Jun 3 '09 at 17:43
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I'm afraid you would have to back up and restore or create a new RAID1 array using two different disks and copy everything to them.

As you'd backup at the filesystem level, not the block device level, you'd need 300GB of storage.

  • +1 Also advanced raid controllers that can migrate between levels normally only permit "going up" (raid5 add disk, raid1 to raid5, raid5 to raid6) - not down-size:ing or changing to a completely different kind of raid. Migrating a raid0 to raid3 sounds possible in theory but that would need another disk and a controller supporting it ^^ – Oskar Duveborn Jun 3 '09 at 18:17
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Is there any software that will allow it to happen?

I'm not aware of anything and I wouldn't trust anything that claimed to do it. I've seen "proper" hardware RAID controllers that let you do things like add disks to an existing array, but nothing to convert RAID 0 to something else.

My point of view is that you pretty much HAVE to back up in order to be sure your data is safe, and that that point why not just do things the "old fashioned" way anyway?

Do I have to create a complete image of the raid 0; reconfigure and re-format and then restore the image?

You don't have to do it as a disk image as such (though that might be the quickest method) but this is how I would do it.

I currently have 2, 640 gig drives running Raid 0. About 300 gig is currently stored on the array. Would the back-up image be 300 gig or 1.2 terrabytes.

Oh... 300Gb. You back up the files you have, not a bit by bit image of the disk (which would only be 600/640Gb anyway as this is the size of the logical drive that is sitting on your RAID 0 stripe).

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I did this recently with my Alienware laptop (2 x 100GB drives in RAID 0).

I used Norton Ghost ver8 to back up the drives to a plug in USB drive then reconfigured my RAID to RAID 1 and restored my image from Norton Ghost.

The disk size changed (obviously) but Norton Ghost handles it very well.

Hope this helps.

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It there was such a thing it would probably have to be supported by your RAID controller. If you are using some cheap onboard 'failraid' the answer is almost certainly no, there is no way to convert a RAID0 to a RAID1.

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If your using software RAID, i'm going to say its not possible to convert, I can't think of any way to do it. If your using hardware RAID, then it depends on your controller, some controllers have a Migrate feature that may let you do this.

Your best bet though would be to take an image, delete the array and recreate it. Your image should only be the size of the data, so around 300Gb

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Unfortunately the answer is no. RAID 0 (striping) is currently giving you 2 x 640GB (1280GB), whereas RAID 1 (mirroring) would only give you 640GB. Since you only have 300GB worth of data, you need to use one of any number of "disk imaging" tools, of which Symantec's Ghost is the most widely known.

Steps:

  • Create an "image" of the RAID 0 array onto another disk (e.g. a USB drive)
  • Use the array controller's software to delete the existing RAID 0 array and create a new RAID 1 array
  • Restore the image back on to the array

For 300GB this shouldn't take more than a couple of hours all up. The only assumptions are that you need 300GB of spare disk space and access to a disk imaging tool (there are plenty of free and open source ones).

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This is controller-specific (if software RAID, consider the driver (e.g. Linux MD) to be your controller).

Usually in such a migration you have the luxury of extra drives for the migration. In such a case, the answer is yes, and it's easy.

The real question is - what kind of data could be store on a RAID0 and later require migration to RAID1. They fill such wildly differing requirements that the question itself is confusing.

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Some controllers have management software that allow you to "transform" a RAID volume to a different RAID level.

I use a HighPoint RocketRaid 2640 SAS array and the mgmt software is showing the option to convert my RAID 0 to RAID 1.

Not sure if it would actually work. Not gonna try. :)

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Regards to my previous experience about it, You can't.
Because the RAID 0 will strip your disks (eg: 4x1TB -> 4096GB) you can't even take an LVM Snapshot or create a backup from your partition with dd. If you want to change Raid from 0 to 1. it's not possible to do it through simply convert them or take a backup from partitions and restore it.
You have to backup data by yourself file-by-file.

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