Hoping someone can help out what I think should be straightforward (for someone more familiar with the subject than me).
I installed jessie and opted for an encrypted / partition (/dev/sda2), encrypted swap partition (/dev/sda3) and unencrypted /boot partition (/dev/sda1)
Single disk /dev/sda1
All fine so far and the system works fine
Then I installed 4 data disks (when powered down) and the origonal sda is now sde.
Upon boot up the new sda unfortunately has 3 partitions and 1.7TB of data disapeared as it now becomes an encrypted swap partition. However, the system still boots up using sde1 as /boot and sde2 as /
Looking at fstab it looks like / is referenced by UUID (so explains how the system still booted) but swap was referenced by /dev/sda3 (so explains how all the data got wiped from the "wrong" place).
Lesson learned but why is the swap not referenced by a permanent ID which would have prevented this. Why is it done differently to the / partition.
More significantly now my encrypted drive (/) (/dev/sde2) is referred to by device mapper as /dev/mapper/sda2_crypt which is really confusing.
How can I change this?
I updated fstab, crypttab removed the entry in the dmsetup --table and replaced with a renamed equivalent.
Now the system still boots but asks for the encryption key twice and the device names have not changed at all.
I spent hours online but cant see what I need to change, the best page I found was https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt