Another newbie with two Thunderbay 4

I would use CCC as your first idea.

SoftRAID 6 should have a feature to help manage this, but use CCC for now.

Cheers. So now I'm CCC'g my RAID 5 to a second TB4 RAID 5 and it's much quicker than the thunderbolt Drobo. I guess not all thunderbolts are the same.

Okay, all done.
30TB SR RAID 5 CCC'd to a 29TB Drobo 5C
12TB SR RAID 5 CCC'd to a 11TB Drobo 5D, which is also backblazed.

Fingers crossed

Great!

While RAID gives you higher "Data Availability", when a disk fails, it is not the same as backup.

Okay, Drobos are terrible. And also my mac pro 2013 is acting up. Plugging in a TB2 cable into one port causes disconnection of the others. So one of my RAID 5s is being validated, but the other is just showing 'Waiting for disk'. What can I do next please?

Just plugging in a cable causing disconnects usually means that the other cables are not 100% tightly inserted, or may be faulty.

Waiting for disk means a disk is hanging, or missing. Is there a ? in the disk tile, then the disk is hung. Wait until the other is rebuilt (validated), then restart.

Cheers. Apparently it's a known but rare problem with the trashcan mac. It's going to the Apple shop for a check up next week. Currently waiting for one validation to finish (2 hours left), also carbon copying HDD to an external SSD so that I can boot into it from my MBP whilst the MP is in the shop.

Okay, so the first RAID finished validating. I rebooted and the second RAID that was constantly 'waiting' appeared to my relief, although there was then a Softraid message warning about the disks. I opened SR and there were warnings about the volume being degraded, with I/O errors in red for each disk. But not waiting. So I'm validating them now. Fingers crossed.

I'm ready to chuck out my drobos, I'm not sure if I got dud ones, but they are troublesome. I've had to wipe/reformat on several occasions. And most recently I suspect it's messing with my ports. When they come on, my dual display (TB display and HDMI display) goes to HDMI only.

Woah. SR came up with an error with 'an internal component' with 45 minutes left of the validation. And I'm thinking, d*mn. Luckily it does seem to have picked it up where it left off.

Odd. Second RAID validated successfully. I rebooted and it's still showing I/O errors and I'm having to validate again.

And the first RAID I validated also comes up with I/O errors when I plug it back it now. Even though both RAIDs were validated without errors. Odd. I'll take the data and wipe the volumes.

Okay, something else. LOL.

So I decided to forget about validating one volume with dispensible data and wanted to wipe the drives and start again. So I disable safeguard, deleted the volume. Then I tried to make a new RAID volume but it wouldn't complete/ mount, saying that Softraid error creating volume, unable to create file system. Several times. So then I detach the enclosure from my MP2013 and hook it up to my MBP2015 which is going to be my computer when the MP2013 goes in for repair next week. This time creating a new RAID volume was not a problem. Does it have anything to do with the fact that I'd booted the MBP2015 off a SSD cloned with my MP2013 drive? Does SR think now that the MBP2015 version is legit, and the original one on the MP2013 isn't?

Another message. I re-validated the bigger RAID, which took 7 hours. On restarting SR still reports errors. The volume seems to be working okay though, files open up ok. I'm going to carbon copy this volume to another TB4 first, before I try validating again or just deleting the volume and using the CC backup to restore the original RAID.

Did you clear the IO counters? My guess if you expected the validate to clear the counters. They are independent. Validate resets all parity bits and assures the volume is readable..

No, SoftRAID calls an OS X tool to create the file system. You worked around it by connecting to another system. the main way I recommend is reinstall the last "Combo" updater. That usually fixes this.