I currently have a Raid 0 configuration set up with an ICHR9 chipset using Intel Matrix Storage Manager. One of my drives is failing and I was wondering if I could upgrade the raid volume to a Raid 5, remove the failing drive, and then downgrade the volume back to Raid 0.
If not, is there any other way to avoid having to copy all the data off, rebuild, and copy it all back?
No way to avoid the process, and you should start NOW.
When a member of a RAID0 array fails, you may lose ALL your data. So if you know one is threatening to fail, fix the problem immediately.
The only secure way to do that with RAID0 is to make a complete backup of the entire drive's contents to another device. Then at LEAST do a verification of the backup to be sure it's good. If possible and you're very cautious, make a second separate backup, too.
AFTER you have the full backup, go to work on the array. Check the RAID management system you have to identify which HDD is showing problems. Then you break the array back to individual HDD's and replace the faulty one. At this point it's a good idea to do thorough tests on the other HDD unit also in case it has minor problems you can fix now. Then you re-create the RAID0 array, and restore everything from the backup.
There really is NO way to convert a RAID0 directly to a RAID5 array, and certainly no way to do the reverse. What is necessary in each case is to do the full backup, break up the existing RAID array, install the necessary new drive units, create the new RAID array, then restore the backup to the new "disk" (that is, RAID array).
The Intel Matrix Storage Manager has the option to upgrade a Raid-0 to a Raid-5, but it doesn't look like I can go backwards. I really don't want to rebuild my array and I was hoping I could image the drive, but I guess I am out of luck.
But you can image the array. If you were considering converting from a RAID0 to a RAID5 array, surely you were planning to add to the array at least one HDD unit. The RAID0 probably has 2 HDD's, and a RAID5 has a minimum of 3.
So, INSTEAD of converting to a RAID5 array, IF your third drive is large enough to contain ALL of the current contents of the RAID0 array, you can use that third HDD for the "image". Recognize that, although a RAID0 array contains 2 HDD units, as far as the OS is concerned it is ONE "drive". You could make an image of its contents to the third unit, then proceed. (Break the array, replace the faulty unit with a fourth HDD, then re-create the RAQID0 array.) THEN you restore the image back to the repaired array.