Degraded RAID set RS1 - No spare available for rebuild

When one of the drives in a redundant RAID like your RAID-5 is missing or has an I/O Error, the RAID card subsystem declares the array "degraded" and continues without the problem Drive.

Since it is no longer viable, that drive is ignored, and the first write to the array with that drive disabled means that drive is out-of-date. So even if it were working perfectly, it cannot be re-added to the RAID set and have it continue. It theoretically could be quick-erased and re-added as a spare, but that is not my recommendation.

I suggest you use Disk Utility to erase that drive with Security Options: Zero all data, one pass [one click to the right from the default settings]. This writes known-good data into every block, and encourages the drive to substitute spares for any blocks found to be bad after writing. If it passes that process, it has 100 percent good blocks again. If it fails, it is a doorstop.

Once you have a Zeroed drive (which takes several hours but can be run in the background) you can add it to the RAID set as a spare, and it will be brought up to date and become a team member again.

You may also want to consider buying an additional drive of the same type, or several new ones to build a different (larger) array. The Apple RAID card is still limited to drives 2.2TB/drive maximum.

On your bottom screen shot, no info is shown for the drive in Bay 3.

In the top screen shot, the error message says "drive 3: 500..... is missing, Previous status was inuse."

Hi: I am having the exact issue as you. Have you found a solution as to how to erase (zero) the one drive that is part of the RAID? Should we just replace the drive?

There are command line Utilities that can be used to break that drive out of the RAID, but they are very sharp and will cut you if not extremely careful. Normally you would pull the un-involved drives (so that they are not damaged by this operation and so that the complete RAID is not mounted) and boot from an alternate source of software, and use Disk Utility to Zero that one drive.

You appear to have made the unfortunate choice of creating one huge array for ALL your stuff, which makes this very difficult indeed. If you have a bootable DVD, you could use 10.6 Installer/Utilities DVD and its on-board Disk Utility to zero the [entire] troublesome drive by itself. You could also download Recovery Disk Asssitant, and write a Recovery_HD (about 0.25GB) to an external drive (any external, including a thumb drive) then boot from that and use its Disk Utility.

Presuming that the troublesome drive passes Zeroing, you can then go back to the full System and use RAID Utility. Add your newly-Zeroed drive to the Array as a spare. At that point, the RAID partition will be re-written with the RAID Drivers, and then the drive can be added to the set.

Rotating drives collected into a RAID get additional speed from overlapped I/O. While one drive is transferring data, the next drive(s) are doing their 20msec or so seek to the next track. But this only works for as long as you stay reading/writing the same Big file.

If you include the Boot Drive in your RAID, it "snacks". It reads a few more blocks of an Application program, writes a Page to the Paging file, reads a system overlay, writes an entry in a log file. This moves the Read/Write heads away from your data files and makes every access to data much slower, wrecking RAID performance.

The biggest overall performance payback you can give a multi-drive capable Mac is to establish a Boot Drive, with only System, Library, Applications, and the hidden unix files including Paging/sawp. All User files are moved off to other drives.

Thank you for trying to help me. It turns out that my drive #1 is where my system is located. I have 3 other drives (in bays 2,3,4) which make up my RAID 5. My drive in bay 2 appears to be the one that is "not responding or has been removed from the system" according to my RAID utility. I have a RAID card installed since I purchased this Mac Pro 2 x 3 GHz Quad-Core Intel Xeon. Should I just rplace the drive in bay #2 or is there a way to erase (zero) that one drive? Thanks again.

Pull the un-involved drives (so that they are not damaged by this operation and so that the complete RAID is not mounted).

Since you have a Boot Drive outside the RAID, use Disk Utility to Zero that one drive. It takes several hours, but can be done in the background.

Erase > Security Options > one click to the right from the default is Zero all Data, one pass.

Thank you ever so much!

Sooooooo

When I had just my boot drive and the one bad drive in the computer (having pulled bay 3 and 4), my disc utility does not see the drive in bay 2 at all. I presume this means I need to replace the drive, or do you think I can just erase the entire RAID? It's backed up on 2 separate external drives. thanks

If the drive is not seen at all, It sounds like it has died.

You may want to confirm that by looking at

About this Mac > ( More Info ) > Hardware RAID ...

... and see if the drive appears there or under SATA.

If you want to keep your RAID, replace the drive with a new one that is similar, add the new drive to the RAID set, and ask it to rebuild the set.