SuSE

Hello, I have a file server running openSuse 11.1, that has two HDDs running in RAID 0 (mirroring) using the md software RAID linux driver. I was considering removing this RAID, using one of the drives as the OS and the other as a data drive. Is there any way to stop using this as a RAID set to do this, or am I going to have to reinstall (I hope that isn't necessary!!). Any insight would be GREATLY appreciated...

RAID 0 is not mirroring. If you are using RAID 0, I'd back that up fast, and switch to RAID 1, which IS mirroring. If you break the RAID you will lose your data.

What you CAN do, to accomplish what you want is this.

using the mdadm command mark 1 drive as failed and remove it from the array. Then, you can format the drive and use it for data. If at any other point, and I'd suggest you do this, you wish to use a third drive or a portion of a third drive to mirror again, you can use that partition and rejoin it to your array.

Sorry I misspoke... It is RAID 1. I remember setting it up a bit ago, but didnt correctly remember the number. Does that change the later part of your answer, as far as how to use of the drives for data?

---------- Post updated at 01:21 PM ---------- Previous update was at 01:19 PM ----------

Marking one as failed... Is that going to cause any system overhead, with the system looking for a second drive?

No, it does not change anything. If you had RAID 0 you would have no way to recover save for backing everything up and starting over, or adding 2 more drives and becoming a RAID 0+1 set.

If you mark a drive as failed you will lose it as part of the array. If you lose the other drive, then you will lose the machine, as if you had only a single drive load set.

There will be a small overhead shift, as you will no longer incur the write penalty for RAID 1, but will also no longer get the read performance increase that RAID 1 provides.

What you are doing is this:
1) logically "failing" a drive, to stop the sync to the mirror
2) removing the formerly mirrored drive from the array to re-purpose.

You should do an mdadm --zero-superblock to the drive you have removed (AND ONLY to that drive). Then you should also fdisk it and change the partition types to the appropriate types, in case it was set as RAID. From there you can proceed to using the drive as any other drive.

I would strongly advise you make a system backup JUST in case, as any disk re-purposing can go wrong.

Thanks a lot for all of the info. I was really worried that I would have to reinstall, as I have everything set up just right (well, except for the drive situation!) and that would be a real pain to try to do between jobs at work.
My two concerns were 1) having to reinstall, and 2) confusing the system (and suffering from performance/stability issues) since there will no longer be a RAID set installed.
It looks like that won't be too big of an issue...
Thanks again!