My MacBook Pro typically backups to my iMac Time Machine server. I went on a year long trip, during which time I switched my MBP to instead back up to my router (which acts as a NAS and runs a Time Machine server of its own, which writes to a sparsebundle). Now that I'm back from my trip, I would like to resume backing up my MBP to my iMac.
I would like to "merge in" the backups from my NAS's sparsebundle, so that my iMac has the full history. Is this possible?
Original Time Machine destination: A sparsebundle hosted by my iMac
$tree -L 1 /Volumes/old_backup_sparse_bundle/Backups.backupdb/Alex's\ MacBook\ Pro
/Volumes/old_backup_sparse_bundle/Backups.backupdb/Alex's\ MacBook\ Pro
├── 2017-12-29-033257
├── 2018-01-06-141057
├── 2018-01-13-041417
⋮
├── 2018-03-03-094036
├── 2018-03-07-233939
├── 2018-03-08-001351
└── Latest -> 2018-03-08-001351
Temporary Time Machine destination: A sparsebundle hosted by my router
$ tree -L 1 /Volumes/newer_backup_sparse_bundle/Backups.backupdb/Alex's\ MacBook\ Pro
/Volumes/newer_backup_sparse_bundle/Backups.backupdb/Alex's\ MacBook\ Pro
├── 2018-10-14-091702
├── 2018-10-21-100253
├── 2018-11-01-202140
⋮
├── 2019-03-03-192937
├── 2019-03-04-142255
├── 2019-03-04-153448
└── Latest -> 2019-03-04-153448
Desired outcome: My iMac's sparebundle is backfilled with the router sparsebundle's snapshots:
$tree -L 1 /Volumes/newer_backup_sparse_bundle/Backups.backupdb/Alex's\ MacBook\ Pro
/Volumes/newer_backup_sparse_bundle/Backups.backupdb/Alex's\ MacBook\ Pro
├── 2017-12-29-033257 ┐
├── 2018-01-06-141057 │
├── 2018-01-13-041417 │
⋮ │ Already present in this sparsebundle
├── 2018-03-03-094036 │
├── 2018-03-07-233939 │
├── 2018-03-08-001351 ┘
├── 2018-10-14-091702 ┐
├── 2018-10-21-100253 │
├── 2018-11-01-202140 │
⋮ │ "Merged in" from the router's sparsebundle sparsebundle
├── 2019-03-03-192937 │
├── 2019-03-04-142255 │
├── 2019-03-04-153448 ┘
└── Latest -> 2019-03-04-153448