Raid sometimes mounts.

[Algr]

Hi Everyone!

So I put three of my old drives together in a JBOD raid. (8+8+4TB) I set it to be the Time Machine backup for my new drive. (16 TB) Everything seemed to work fine, and it copied everything to the backup. I was even able to copy back some test files. But now it usually refuses to mount on the desktop. Sometimes it mounts, mostly it doesn't. I've tried all sorts of configurations, with two different hubs and connecting it directly to my Studio. I got it working for a few days and thought that maybe it had to be non-thunderbolt ports for some reason? But now it won't mount again. The disks show up in Disk Utility. I can first aid the media, and all three disks report fine, but using first aid on the whole raid is greyed out. Below are the errors. The phase of the moon is not relevant.

Can anyone help? Thank you!

 

[Fishrrman]

"So I put three of my old drives together in a JBOD raid"

Hmmmmmmmm......
Seems to me that JBOD (just bunch of disks) and "raid" are two COMPLETELY DIFFERENT things.

Do you want the drives in one enclosure, but all showing up as "standalone drives"?

Or do you want them "together"?

Sounds like something isn't set up right -- perhaps "configurable switches" on the enclosure, or software...?

 

[Algr]

I used Disk Utility to make the raid, and it calls it a raid. JBOD is listed as one of the raid modes. JBOD is the raid mode that allows disks of different types and sizes to be used together efficiently and appear as one disk.

Do you want the drives in one enclosure, but all showing up as "standalone drives"?

The opposite. They are three external USB drives, appearing as one drive on the desktop. I did this because none of them are as big as the drive I want to back up, and Time Machine can't use them separately.

 

[Fishrrman]

"I did this because none of them are as big as the drive I want to back up, and Time Machine can't use them separately."

I'm not a tm user.
But this sounds like a recipe for disaster. Or, a backup that won't work right when you need it.

 

[Algr]

So what is the alternative? I've got a new 16 TB drive, and the older drives are 8, 8, and 4 TB. If one of the older drives fail, Time Machine would tell me right away, wouldn't it?