On 2020-08-19 03:03, Urs Thuermann wrote:
David Christensen <dpchrist@holgerdanske.com> writes:
When using a drive as backup media, are there likely use-cases that benefit from configuring the drive with no partition, a single PV, single VG, single LV, and single filesystem vs. configuring the drive with a single partition, single UUID fstab entry, and single filesystem?You can use a partition or the whole disk for a physical volume
Yes.
... I prefer having a partition table with only one partition covering the whole disk. The partition table entry includes a type so that there is less guessing about what the disk contains:
This is especially true if you access the drive with foreign operating systems.
If you then put a single LV into the VG which covers the whole VG you don't benefit much from LVM's functionality, except that you caneasily change allocations later if you decide so.
Some backup tools, such as macOS Time Machine and Windows File History, automatically delete old backups if and when the destination filesystem becomes full. So, one use-case would be if the drive were the destination for several such backup tools -- use LVM to subdivide the available space among them.
Another use-case is enlarging the backup filesystem by adding another drive. Another use-case is mirroring the backup filesystem.A more complex mirroring use-case -- add, re-silver, and remove drives, and rotate them on-line, on-site, near-site, off-site, etc..
Re-partitioning is more complicated.
For a drive used as a PV for backups, I cannot think of a use-case for re-partitioning.
David