I recently recreated a disk / vm image in google compute from a previous set of snapshots. Those snapshots are currently dated and sized as follows:
- May 20 60 MB - May 21 372 MB - May 22 255 MB - May 23 118 MB - May 24 93 MB - May 25 1110 MB
After creating the disk I took the original source disk off-line (stopped the VM), made the new disk the boot disk, and started it. I then saved a machine image of it, and then did a manual snapshot. The new snapshot:
May 25 16 MB
I don’t have an image to verify, but I’m fairly certain the original May 20 snapshot was 300+ MB.
As subsequent snapshots obsolete parts of existing snapshots, are the obsolete files “taken-out” of the preceeding snapshot? I.e. the snapshot is uncompressed, pieces removed, and then recompressed?
Why is the first snapshot of the newly created disk so small? It looks like it must be linked to the snapshot series of the disk from which it was created.
Note: the snapshot schedule for the original disk was disconnected from it and re-used with the new disk.
What happens to the snapshot of the newly created disk if the series from the first disk is deleted? Is it invalidated? Or are the originals “rolled into it”?
Can someone explain to me what is going on?