Cloning a NAS hard drive with OS

[mjz]

ddrescue update:

Still chugging along:

65.2% complete after 2 days 2 hours running.
remaining time estimate: 1 day 1 hour
Average transfer rate: 15.1 MB/sec
1.3 Terrabytes to go on a 4 TB disk

[mjz]

Good morning ....

ddrescue update at 9:00 a.m.

81.6% complete after 2 days 15 hours running.
remaining time estimate: 13 hours
Average transfer rate: 15.1 MB/sec
0.73 Terrabytes to go on a 4 TB disk

Read errors logged so far = 5
error rate = 0 B/sec
bad sector = 0 B

(Having never used ddrescue before, I am curious what happens when the process reaches 100% complete. I assume it will try and scrape the sectors where read errors occurred)

[TrevorH]

I think when it gets to the end then it is done. All the retries happen during the copy so anything that needs retrying in the data that is already copied is already done.

[mjz]

... we'll know in 5 hours!

[mjz]

Copy complete. 99.9% recovered
I was able to boot the new drive, but the system reports "no raid volume".
It seems this process was for naught.

(I have the data backed up. It seems what I could have done is reload the OS from binary and rebuild the volume with a traditional copy (or FTP). It would have taken a lot less time. It would not be "identical" as I don't have all of the settings which the clone would have, but it would be restored albeit differently)

[mjz]

sdb is the old drive & sdc is the new one.
sdb 8:16 0 3.6T 0 disk
├─sdb1 8:17 0 2G 0 part
│ └─md127 9:127 0 2G 0 raid1
├─sdb2 8:18 0 3.6T 0 part
├─sdb3 8:19 0 1G 0 part
├─sdb4 8:20 0 1G 0 part
├─sdb5 8:21 0 1G 0 part
├─sdb6 8:22 0 2G 0 part
└─sdb7 8:23 0 1G 0 part

The information above was from the original drive.
The new drive lists the same partitioning EXCEPT, Md127 is not there (i.e. raid1).

[TrevorH]

It's presumably looking for the RAID device by something that did not copy. If you look under the /dev/disk/by-* directories you can see all of the ways in which it might find it. Your NAS presumably also has a way to configure mdadm (they are usually linux under the covers) to tell it about the new disk. I've seen mdadm set up to find arrays by UUID, by LABEL, by full /dev/sdX[n] path and I suspect there are more.

What model of NAS is it?