Is collectd by Disk Label possible?

Because the disk device numbers can, and do, change between boots. So tracing the history across multiple disks is impossible.

Cheers.

Sorry for the late response, what do you mean? Label your disks on collected? How?
Can you paste some screenshot and editing proposals?

AFAIK the device numbers don’t change between boots. They can or do change with every boot. So e.g. /dev/sda can be phisically another drive after reboot, but collectd (CGP) can only show sda, sdb, etc.
Refering to this https://www.kernel.org/doc/Documentation/iostats.txt I don’t think that it’s possible what you want, because it seems that collecd gathers data from /proc/diskstats (kernel 2.6)
You can have also a look on this: https://collectd.org/wiki/index.php/Plugin:Disk