RAID set "Degraded": how to repair?

So you use an external case, with a stripe array, and it says "degraded?"
Seems degraded is mentioned for mirror.
http://reviews.cnet.com/8301-13727_7-10330310-263.html
http://support.apple.com/kb/HT3305

And you created the array in Disk Utility.

Dual drive case, some of which have built in bridge that can enable its own RAID.

And you are doing this over a FW800 connection?

Is that basics?

RAID 0 doesn't permit for a "degraded" state. RAID 1 does, perhaps that is what you have.

In RAID 0, data is spread evenly across two disks without parity (error checking) or duplication. If one of the disks experiences a fault, all data on the RAID is lost. The idea of RAID 0 is that you are sacrificing the integrity of the data for speed.

RAID 1 mirrors the disks, so one is always a replica of the other. It has a degraded state where 1 drive has a fault, and the fail-over condition is that the RAID switches to using a single disk (until the defective drive is replaced).

RAID 0 has no repair options.

RAID 1 has a single repair option: to replace the defective drive with one of equal or higher capacity.

Other than replace the faulty drive, there's really nothing you need to do. The RAID software should take care of the rest.

USB with its high cpu overhead, and very slow I/O is a horrible interface to start with (at least until USB 3 is out) and more than half as slow as the native speed of any single drive today.

So you tried to setup three partitions on those two 500GB drives. And do it over USB, and wondering why it is having trouble?

Any RAID, mirror or otherwise, should be backed up.

Delete what you have and use as single drives and just clone the primary data to the other... as needed for proper backup.

I've only seen that when a drive in the array was malfunctioning or had a loose connection.

USB2 = less than 40MB/sec, and without adding PCI Express or something, there is only one bus/channel shared by all USB devices.

A non-RAID will run faster and better.

Hi majortom67;

What is your reason for using a RAID0 array? Exactly what do you hope to gain with it?

It certainly doesn't sound from the way you are going about implementing it that this is the correct solution so I would like to know what problem you are solving here.

Allan

You are killing your USB ports and other devices. You aren't getting anything, and your mirror isn't cutting it (and made more complex by having three volumes).

Sounds like you also have too many 'boxes' - again, there is one FireWire bus, and one USB.

Putting two drives on one, daisy-chaining, etc.

Even Mac Pro with independent controllers and the rest wouldn't do what you attempting, and USB/eSATA or quad-interface have their problems.

RAID-0 isn't mirrored. That'd be RAID-1. You'd use RAID-0 for performance, with the understanding that RAID-0 jeopardizes the data (if either drive fails, all of the data is lost). RAID-1 you'd use to increase your chances of recovery, if one drive fails, the other drive is an exact duplicate; if the RAID controller fails, the drive can be moved to a new one and be expected to work.