identify persistent ID for each device

[trgill]

To use the database over reboots, we need to easily match devices. Some subsystems already have persistency in them (e.g. the LV UUID, MD UUID, scsi serials/WWNs...), but it doesn't apply for all Also, the format is not standardized (...let's compare that to network device name standards as defined by systemd). Also, we probably need to differentiate real device types vs. virtual/metadata-based devices.

Any of the application created UUID's can end up with duplicates when a block device gets duplicated.

What is the plan for SID to handle this?

Issue copied from email exchange with @prajnoha and @tasleson