Cure for crash after creating a RAID group on external drives?

I know this is an old discussion but I'm having the same problem.

I have 2 4TB HDs that I wanted to set up as RAID to mirror each other. I went ahead and did so and now whenever they're both plugged in it crashes my Mac (OS X 1012.5 Sierra). I now see that setting it for 256kb data chunks might be the problem.

Here's the catch. If I plug one drive in the Mac will see it for about 30 seconds before it crashes. In that time I can't erase the drive as it's not an option in Disk Utility for the drive. I've tried hooking it up to a Windows machine but it's unrecognizable. Any other ideas on how I can get these drives wiped clean and start from scratch?

I can confirm this. Lion 10.7.1 - A RAID 1 mirror across two devices (4GB USB sticks) with a block size of 256k crashes the OS. Lion will continue to crash whenever it tries to mount the RAID volume.

Interestingly, if I create a RAID mirror on a second machine installed with Leopard, same specs, 256k block size etc, and then mount it on Lion I don't see the crash.

A RAID set with a 128k block size does not produce crashes.

It would be good if someone could fix this.

i can confirm that the problem is existing in 10.7.5 on a xserve

when you connect a raid 1 with 256kb blocksize the machine will be crash... also a macbook pro with 10.7.5

10.8.3 i dont yet testet, my xserve will not be able to 10.8

Unforunately I found this thread after I tried to make a RAID set with 256K and as soon as it did. My Mac crashed. It will start upo fine as long as the two hard drives are not connected. So how did you guys fix this? I only have one Mac.

do you have another computer ? windows or linux all the same.

then reinitialize the disk's and put again in your mac. Create a new raid1 (mirror) to maximal 128kb

regards,

Pat

I have a windows PC. I tried connecting HD's to it but with no luck. It will not recognize them. It's two HD's in a single enclosure. Not sure how to reinitialize them if Windows PC cant see them or any Mac crashes when I connect it.

Thank you for your fast response!

Mike

Try booting the Mac into recovery mode (google it), then use the disk utility there to either create a new RAID with 128k blocks, or just format both drives as normal and then you should be able to access them from the desktop again.

Alex

I was able to get into the Recovery without any issues but still every time I connect my USB cord it crashes my Mac. And it seems without being able to connect it to anything I cannot reformat or change the block size.

Mike

ok i know this issue in max osx 10.7.5 i had it too yesterday with 2x 4TB Harddrive but i do it on an older mac system in my case 10.6.8

but you can do under windows, use this link to re format/initialize a drive as ntfs

http://www.brighthub.com/computing/hardware/articles/22069.aspx

hope this helps you

regards,

Pat

I set up a mirror raid on two external USB drives, and set to 256k under osx 10.7.5 then got the full melt down

and the same every time i tried to reformat the drives.

I did notice a slight moment of time when opening disk utility before the crash!

The following worked for me.

Start the computer, insert just one of the USB or Firewire drives then open disk utility.

Here is the key point as fast as you can select the drive icon as soon as it appears on the left and hit the erase option

don't worry about the type of format select the t hit the erase button as quickly as you can and again as the prompt comes up are you sure you want to erase the disk.

Then repeat again on the second drive and then start the raid set up over again with blocks set at 128k.

Probably advised to unmount all other drives so you do not accidentally format the wrong drive given this is all about haste.

Really hope this helps and think it through as to how it relates to your set up.