Ubuntu 20.04 snapshots are failing. "error during transition to incremental ioctl handler"

[IT-Roman]

Ubuntu 20.04 running as Gen 2 Hyper-V VM.
After installing the agent and running the first backup I saw the following error in dmesg, but the Datto portal shows backup as successful:

[ 2185.984433] datto: device specified is busy: -16
[ 2185.985037] datto: error during transition to incremental ioctl handler: -16

After that, every attempt at a snapshot generates the same two errors and snapshot fails.
Here's a log from the last snapshot attempt:

Tue 11/04/23 1:20:38 pm - Backup operation completed.
Tue 11/04/23 1:20:38 pm - Alert Service not enabled
Tue 11/04/23 1:20:38 pm - Backup failed with exception
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Releasing backup lock
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back to snapshot
Tue 11/04/23 1:20:38 pm - Setting properties on storage
Tue 11/04/23 1:20:38 pm - SnapRollback Started.. mode rollback
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Cleanup found no leaked loops.
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Transaction failed. Rolling back ...
Tue 11/04/23 1:20:38 pm - Failed to complete transaction stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Failed to complete stage PrepareAgentVolumes, rolling back
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Successfully rolled back stage
Tue 11/04/23 1:20:38 pm - Rolling back stage
Tue 11/04/23 1:20:38 pm - Transaction failed. Rolling back ...
Tue 11/04/23 1:20:38 pm - Agent Export error occurred mid transfer (SNAPSHOT - Could not destroy snapshot.)
Tue 11/04/23 1:20:38 pm - 1681237222 [] Requesting cancelation of backup ID 2e3416e6-e74e-49d0-be02-d034297fd6ff
Tue 11/04/23 1:20:38 pm - 1681237221 [] SleepPolicyNever is no longer controlling sleep state.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Backup run finished
Tue 11/04/23 1:20:38 pm - 1681237221 [] Backup 2e3416e6-e74e-49d0-be02-d034297fd6ff FAILED!
Tue 11/04/23 1:20:38 pm - 1681237221 [] Finished execution of the Transition To Incremental phase.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Failed to transition volume 35a5038f-a168-445d-b400-07f66babd05f (/boot) to incremental. This volume may diff-merge next backup.
Tue 11/04/23 1:20:38 pm - 1681237221 [] driver device /dev/sda2 minor 1 is not in active snapshot state. Current state 2
Tue 11/04/23 1:20:38 pm - 1681237221 [] Failed to transition volume ed07469d-5865-44fe-9dcb-45f2dd68ed2d (/) to incremental. This volume may diff-merge next backup.
Tue 11/04/23 1:20:38 pm - 1681237221 [] error on driver device after transition_incremental failure for device /dev/dm-0 minor 0 device error 0
Tue 11/04/23 1:20:38 pm - 1681237221 [] error from calling transition_incremental for device /dev/dm-0 minor 0 error -1 errno 16
Tue 11/04/23 1:20:38 pm - 1681237221 [] calling transition_incremental for device /dev/dm-0 minor 0
Tue 11/04/23 1:20:38 pm - 1681237221 [] Failed to revert device /dev/sda2
Tue 11/04/23 1:20:38 pm - 1681237221 [] Could not find starting state for volume /dev/sda2
Tue 11/04/23 1:20:38 pm - 1681237221 [] Cannot make history, cannot open incremental file errno 2
Tue 11/04/23 1:20:38 pm - 1681237221 [] Failed to revert device /dev/dm-0
Tue 11/04/23 1:20:38 pm - 1681237221 [] Could not find starting state for volume /dev/dm-0
Tue 11/04/23 1:20:38 pm - 1681237221 [] Cannot make history, cannot open incremental file errno 2
Tue 11/04/23 1:20:38 pm - 1681237221 [] Failed to unmount /tmp/dattoMountRoot/ed07469d-5865-44fe-9dcb-45f2dd68ed2d(errno 16)
Tue 11/04/23 1:20:38 pm - 1681237221 [] Beginning execution of the Transition To Incremental phase.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Backup error occurred during backup run Could not destroy snapshot. (SNAPSHOT)
Tue 11/04/23 1:20:38 pm - 1681237221 [] Finished execution of the Backup Pass Finalization phase.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Beginning execution of the Backup Pass Finalization phase.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Exception caught trying to create snapshots Could not destroy snapshot.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Volumes Unquiesced
Tue 11/04/23 1:20:38 pm - 1681237221 [] Unquiescing volumes...
Tue 11/04/23 1:20:38 pm - 1681237221 [] error destroying minor 0 error -1 errno 16
Tue 11/04/23 1:20:38 pm - 1681237221 [] Device ed07469d-5865-44fe-9dcb-45f2dd68ed2d not in active incremental state, destroying snapshot
Tue 11/04/23 1:20:38 pm - 1681237221 [] Validating snapshot session...
Tue 11/04/23 1:20:38 pm - 1681237221 [] Volumes Quiesced
Tue 11/04/23 1:20:38 pm - 1681237221 [] Quiescing volumes...
Tue 11/04/23 1:20:38 pm - 1681237221 [] Beginning execution of the Start Snapshotting phase.
Tue 11/04/23 1:20:38 pm - 1681237221 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'bb9ab0a2-a885-4961-89c4-423537130b48' (Actual) '2e3416e6-e74e-49d0-be02-d034297fd6ff' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'bb9ab0a2-a885-4961-89c4-423537130b48' (Actual) '2e3416e6-e74e-49d0-be02-d034297fd6ff' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Preloading done, starting final pass for backup id 2e3416e6-e74e-49d0-be02-d034297fd6ff
Tue 11/04/23 1:20:38 pm - 1681237220 [] Finished execution of the Validate Remote Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] The cached volume checksum matched the remote volume checksum (24abe5e3) for volume 35a5038f-a168-445d-b400-07f66babd05f
Tue 11/04/23 1:20:38 pm - 1681237220 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'bb9ab0a2-a885-4961-89c4-423537130b48' (Actual) '2e3416e6-e74e-49d0-be02-d034297fd6ff' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237220 [] The cached volume checksum matched the remote volume checksum (e5ee8a67) for volume ed07469d-5865-44fe-9dcb-45f2dd68ed2d
Tue 11/04/23 1:20:38 pm - 1681237220 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'bb9ab0a2-a885-4961-89c4-423537130b48' (Actual) '2e3416e6-e74e-49d0-be02-d034297fd6ff' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Beginning execution of the Validate Remote Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Finished execution of the Validate Local Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Beginning execution of the Validate Local Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Finished execution of the Create Transports phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Backup transport interface MercuryFTP (TLS)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Backup transport interface MercuryFTP (TLS)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Beginning execution of the Create Transports phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Finished execution of the Restore Resume State phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'bb9ab0a2-a885-4961-89c4-423537130b48' (Actual) '2e3416e6-e74e-49d0-be02-d034297fd6ff' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'bb9ab0a2-a885-4961-89c4-423537130b48' (Actual) '2e3416e6-e74e-49d0-be02-d034297fd6ff' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237220 [] Beginning execution of the Restore Resume State phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Finished execution of the Populate Volumes phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Beginning execution of the Populate Volumes phase.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Beginning running backup phases...
Tue 11/04/23 1:20:38 pm - 1681237220 [] SleepPolicyNever is controlling sleep state.
Tue 11/04/23 1:20:38 pm - 1681237220 [] Backup run beginning...
Tue 11/04/23 1:20:38 pm - 1681237220 [] Launching backup thread...
Tue 11/04/23 1:20:38 pm - 1681237220 [] Creating backup 2e3416e6-e74e-49d0-be02-d034297fd6ff
Tue 11/04/23 1:20:38 pm - 1681237220 [] Driver version 0.11.2.0, Agent version 3.0.16.0
Tue 11/04/23 1:20:38 pm - 1681237220 [] Backup engine beginning creation of backup 2e3416e6-e74e-49d0-be02-d034297fd6ff
Tue 11/04/23 1:20:38 pm - 1681237220 [] Generated new backup ID 2e3416e6-e74e-49d0-be02-d034297fd6ff
Tue 11/04/23 1:20:38 pm - 1681237220 [] Backup transport interface mercuryftp
Tue 11/04/23 1:20:38 pm - 1681237220 [] Handling backup start call
Tue 11/04/23 1:20:38 pm - 1681237107 [] Requesting cancelation of backup ID bb9ab0a2-a885-4961-89c4-423537130b48
Tue 11/04/23 1:20:38 pm - 1681237106 [] SleepPolicyNever is no longer controlling sleep state.
Tue 11/04/23 1:20:38 pm - 1681237106 [] Backup run finished
Tue 11/04/23 1:20:38 pm - 1681237106 [] Backup bb9ab0a2-a885-4961-89c4-423537130b48 FAILED!
Tue 11/04/23 1:20:38 pm - 1681237106 [] Finished execution of the Transition To Incremental phase.
Tue 11/04/23 1:20:38 pm - 1681237106 [] Failed to transition volume 35a5038f-a168-445d-b400-07f66babd05f (/boot) to incremental. This volume may diff-merge next backup.
Tue 11/04/23 1:20:38 pm - 1681237106 [] driver device /dev/sda2 minor 1 is not in active snapshot state. Current state 2
Tue 11/04/23 1:20:38 pm - 1681237106 [] Failed to transition volume ed07469d-5865-44fe-9dcb-45f2dd68ed2d (/) to incremental. This volume may diff-merge next backup.
Tue 11/04/23 1:20:38 pm - 1681237106 [] error on driver device after transition_incremental failure for device /dev/dm-0 minor 0 device error 0
Tue 11/04/23 1:20:38 pm - 1681237106 [] error from calling transition_incremental for device /dev/dm-0 minor 0 error -1 errno 16
Tue 11/04/23 1:20:38 pm - 1681237105 [] calling transition_incremental for device /dev/dm-0 minor 0
Tue 11/04/23 1:20:38 pm - 1681237105 [] Failed to revert device /dev/sda2
Tue 11/04/23 1:20:38 pm - 1681237105 [] Could not find starting state for volume /dev/sda2
Tue 11/04/23 1:20:38 pm - 1681237105 [] Cannot make history, cannot open incremental file errno 2
Tue 11/04/23 1:20:38 pm - 1681237105 [] Failed to revert device /dev/dm-0
Tue 11/04/23 1:20:38 pm - 1681237105 [] Could not find starting state for volume /dev/dm-0
Tue 11/04/23 1:20:38 pm - 1681237105 [] Cannot make history, cannot open incremental file errno 2
Tue 11/04/23 1:20:38 pm - 1681237105 [] Failed to unmount /tmp/dattoMountRoot/ed07469d-5865-44fe-9dcb-45f2dd68ed2d(errno 16)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Transition To Incremental phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Backup error occurred during backup run Could not destroy snapshot. (SNAPSHOT)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Finished execution of the Backup Pass Finalization phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Backup Pass Finalization phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Exception caught trying to create snapshots Could not destroy snapshot.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Volumes Unquiesced
Tue 11/04/23 1:20:38 pm - 1681237105 [] Unquiescing volumes...
Tue 11/04/23 1:20:38 pm - 1681237105 [] error destroying minor 0 error -1 errno 16
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device ed07469d-5865-44fe-9dcb-45f2dd68ed2d not in active incremental state, destroying snapshot
Tue 11/04/23 1:20:38 pm - 1681237105 [] Validating snapshot session...
Tue 11/04/23 1:20:38 pm - 1681237105 [] Volumes Quiesced
Tue 11/04/23 1:20:38 pm - 1681237105 [] Quiescing volumes...
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Start Snapshotting phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Actual) 'bb9ab0a2-a885-4961-89c4-423537130b48' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Actual) 'bb9ab0a2-a885-4961-89c4-423537130b48' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Preloading done, starting final pass for backup id bb9ab0a2-a885-4961-89c4-423537130b48
Tue 11/04/23 1:20:38 pm - 1681237105 [] Finished execution of the Validate Remote Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] The cached volume checksum matched the remote volume checksum (24abe5e3) for volume 35a5038f-a168-445d-b400-07f66babd05f
Tue 11/04/23 1:20:38 pm - 1681237105 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Actual) 'bb9ab0a2-a885-4961-89c4-423537130b48' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237105 [] The cached volume checksum matched the remote volume checksum (e5ee8a67) for volume ed07469d-5865-44fe-9dcb-45f2dd68ed2d
Tue 11/04/23 1:20:38 pm - 1681237105 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Actual) 'bb9ab0a2-a885-4961-89c4-423537130b48' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Validate Remote Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Finished execution of the Validate Local Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Validate Local Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Finished execution of the Create Transports phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Backup transport interface MercuryFTP (TLS)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Backup transport interface MercuryFTP (TLS)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Create Transports phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Finished execution of the Restore Resume State phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Actual) 'bb9ab0a2-a885-4961-89c4-423537130b48' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Actual) 'bb9ab0a2-a885-4961-89c4-423537130b48' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Restore Resume State phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Finished execution of the Populate Volumes phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning execution of the Populate Volumes phase.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Beginning running backup phases...
Tue 11/04/23 1:20:38 pm - 1681237105 [] SleepPolicyNever is controlling sleep state.
Tue 11/04/23 1:20:38 pm - 1681237105 [] Backup run beginning...
Tue 11/04/23 1:20:38 pm - 1681237105 [] Launching backup thread...
Tue 11/04/23 1:20:38 pm - 1681237105 [] Creating backup bb9ab0a2-a885-4961-89c4-423537130b48
Tue 11/04/23 1:20:38 pm - 1681237105 [] Driver version 0.11.2.0, Agent version 3.0.16.0
Tue 11/04/23 1:20:38 pm - 1681237105 [] Backup engine beginning creation of backup bb9ab0a2-a885-4961-89c4-423537130b48
Tue 11/04/23 1:20:38 pm - 1681237105 [] Generated new backup ID bb9ab0a2-a885-4961-89c4-423537130b48
Tue 11/04/23 1:20:38 pm - 1681237105 [] Backup transport interface mercuryftp
Tue 11/04/23 1:20:38 pm - 1681237105 [] Handling backup start call
Tue 11/04/23 1:20:38 pm - 1681237037 [] Requesting cancelation of backup ID c3973025-ba1c-4ad8-a6fc-570ff537af8c
Tue 11/04/23 1:20:38 pm - 1681237035 [] SleepPolicyNever is no longer controlling sleep state.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Backup run finished
Tue 11/04/23 1:20:38 pm - 1681237035 [] Backup c3973025-ba1c-4ad8-a6fc-570ff537af8c FAILED!
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Transition To Incremental phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Failed to transition volume 35a5038f-a168-445d-b400-07f66babd05f (/boot) to incremental. This volume may diff-merge next backup.
Tue 11/04/23 1:20:38 pm - 1681237035 [] driver device /dev/sda2 minor 1 is not in active snapshot state. Current state 2
Tue 11/04/23 1:20:38 pm - 1681237035 [] Failed to transition volume ed07469d-5865-44fe-9dcb-45f2dd68ed2d (/) to incremental. This volume may diff-merge next backup.
Tue 11/04/23 1:20:38 pm - 1681237035 [] error on driver device after transition_incremental failure for device /dev/dm-0 minor 0 device error 0
Tue 11/04/23 1:20:38 pm - 1681237035 [] error from calling transition_incremental for device /dev/dm-0 minor 0 error -1 errno 16
Tue 11/04/23 1:20:38 pm - 1681237035 [] calling transition_incremental for device /dev/dm-0 minor 0
Tue 11/04/23 1:20:38 pm - 1681237035 [] Failed to revert device /dev/sda2
Tue 11/04/23 1:20:38 pm - 1681237035 [] Could not find starting state for volume /dev/sda2
Tue 11/04/23 1:20:38 pm - 1681237035 [] Cannot make history, cannot open incremental file errno 2
Tue 11/04/23 1:20:38 pm - 1681237035 [] Failed to revert device /dev/dm-0
Tue 11/04/23 1:20:38 pm - 1681237035 [] Could not find starting state for volume /dev/dm-0
Tue 11/04/23 1:20:38 pm - 1681237035 [] Cannot make history, cannot open incremental file errno 2
Tue 11/04/23 1:20:38 pm - 1681237035 [] Failed to unmount /tmp/dattoMountRoot/ed07469d-5865-44fe-9dcb-45f2dd68ed2d(errno 16)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Transition To Incremental phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Backup error occurred during backup run Could not destroy snapshot. (SNAPSHOT)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Backup Pass Finalization phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Backup Pass Finalization phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Exception caught trying to create snapshots Could not destroy snapshot.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Volumes Unquiesced
Tue 11/04/23 1:20:38 pm - 1681237035 [] Unquiescing volumes...
Tue 11/04/23 1:20:38 pm - 1681237035 [] error destroying minor 0 error -1 errno 16
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device ed07469d-5865-44fe-9dcb-45f2dd68ed2d not in active incremental state, destroying snapshot
Tue 11/04/23 1:20:38 pm - 1681237035 [] Validating snapshot session...
Tue 11/04/23 1:20:38 pm - 1681237035 [] Volumes Quiesced
Tue 11/04/23 1:20:38 pm - 1681237035 [] Quiescing volumes...
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Start Snapshotting phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'f42c0974-ffd5-49b8-8922-4a4770651284' (Actual) 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'f42c0974-ffd5-49b8-8922-4a4770651284' (Actual) 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Preloading done, starting final pass for backup id c3973025-ba1c-4ad8-a6fc-570ff537af8c
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Validate Remote Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] The cached volume checksum matched the remote volume checksum (24abe5e3) for volume 35a5038f-a168-445d-b400-07f66babd05f
Tue 11/04/23 1:20:38 pm - 1681237035 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'f42c0974-ffd5-49b8-8922-4a4770651284' (Actual) 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237035 [] The cached volume checksum matched the remote volume checksum (e5ee8a67) for volume ed07469d-5865-44fe-9dcb-45f2dd68ed2d
Tue 11/04/23 1:20:38 pm - 1681237035 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'f42c0974-ffd5-49b8-8922-4a4770651284' (Actual) 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Validate Remote Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Validate Local Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Validate Local Targets phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Create Transports phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Backup transport interface MercuryFTP (TLS)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Backup transport interface MercuryFTP (TLS)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Create Transports phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Restore Resume State phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Not opening resume file due to differing context. File /boot/datto.rsm | Context Backup ID 'f42c0974-ffd5-49b8-8922-4a4770651284' (Actual) 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Not opening resume file due to differing context. File /datto.rsm | Context Backup ID 'f42c0974-ffd5-49b8-8922-4a4770651284' (Actual) 'c3973025-ba1c-4ad8-a6fc-570ff537af8c' (Expected)
Tue 11/04/23 1:20:38 pm - 1681237035 [] Beginning execution of the Restore Resume State phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Finished execution of the Populate Volumes phase.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237035 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237034 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237034 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237034 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237034 [] Beginning execution of the Populate Volumes phase.
Tue 11/04/23 1:20:38 pm - 1681237034 [] Beginning running backup phases...
Tue 11/04/23 1:20:38 pm - 1681237034 [] SleepPolicyNever is controlling sleep state.
Tue 11/04/23 1:20:38 pm - 1681237034 [] Backup run beginning...
Tue 11/04/23 1:20:38 pm - 1681237034 [] Launching backup thread...
Tue 11/04/23 1:20:38 pm - 1681237034 [] Creating backup c3973025-ba1c-4ad8-a6fc-570ff537af8c
Tue 11/04/23 1:20:38 pm - 1681237034 [] Driver version 0.11.2.0, Agent version 3.0.16.0
Tue 11/04/23 1:20:38 pm - 1681237034 [] Backup engine beginning creation of backup c3973025-ba1c-4ad8-a6fc-570ff537af8c
Tue 11/04/23 1:20:38 pm - 1681237034 [] Generated new backup ID c3973025-ba1c-4ad8-a6fc-570ff537af8c
Tue 11/04/23 1:20:38 pm - 1681237034 [] Backup transport interface mercuryftp
Tue 11/04/23 1:20:38 pm - 1681237034 [] Handling backup start call
Tue 11/04/23 1:20:38 pm - 1681237026 [] Device size 64966656 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237026 [] Device size 52260864 is not evenly divisible by the block size 131072, ignoring 94208 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237026 [] Device size 71106560 is not evenly divisible by the block size 131072, ignoring 65536 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237026 [] Device size 96292864 is not evenly divisible by the block size 131072, ignoring 86016 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237026 [] Device size 66392064 is not evenly divisible by the block size 131072, ignoring 69632 bytes at the end.
Tue 11/04/23 1:20:38 pm - 1681237026 [] Requesting cancelation of backup ID f42c0974-ffd5-49b8-8922-4a4770651284
Tue 11/04/23 1:20:38 pm - Agent logs from this backup attempt below
Tue 11/04/23 1:20:38 pm - Leftover MercuryFTP target cleaned successfully.
Tue 11/04/23 1:20:37 pm - Removing MercuryFTP target.
Tue 11/04/23 1:20:37 pm - End of backup attempt 3 of 3
Tue 11/04/23 1:20:37 pm - Not sending email because there are no recipients.
Tue 11/04/23 1:20:37 pm - Critical Notice will be sent
Tue 11/04/23 1:20:37 pm - Critical Backup Error Email Requested
Tue 11/04/23 1:20:37 pm - Agent Export error occurred mid transfer (SNAPSHOT - Could not destroy snapshot.)
Tue 11/04/23 1:20:22 pm - Waiting 15 seconds after cancelling...
Tue 11/04/23 1:20:22 pm - Datto Agent API request Cancel backup
Tue 11/04/23 1:20:22 pm - Cancelling running backup 2e3416e6-e74e-49d0-be02-d034297fd6ff ...
Tue 11/04/23 1:20:22 pm - Agent Export error occurred mid transfer (SNAPSHOT - Could not destroy snapshot.)
Tue 11/04/23 1:20:22 pm - End of backup attempt 3 of 3
Tue 11/04/23 1:20:22 pm - Agent Export error occurred mid transfer
Tue 11/04/23 1:20:20 pm - Transferring data, 0/-2 [ 0 ] Timeout Countdown 0-900
Tue 11/04/23 1:20:20 pm - Datto Agent API request Start backup
Tue 11/04/23 1:20:13 pm - Waiting 7 seconds for backup transport to setup targets
Tue 11/04/23 1:20:12 pm - Creating MercuryFTP target.
Tue 11/04/23 1:20:12 pm - Adding lun for checksum file
Tue 11/04/23 1:20:12 pm - Adding mercuryFTP lun for backup image
Tue 11/04/23 1:20:12 pm - Adding lun for checksum file
Tue 11/04/23 1:20:12 pm - Adding mercuryFTP lun for backup image
Tue 11/04/23 1:20:12 pm - Using mercuryFTP as data transport
Tue 11/04/23 1:20:12 pm - Attempting to start backup
Tue 11/04/23 1:20:12 pm - Backup transfer attempt
Tue 11/04/23 1:18:42 pm - Waiting before next attempt
Tue 11/04/23 1:18:42 pm - Leftover MercuryFTP target cleaned successfully.
Tue 11/04/23 1:18:42 pm - Removing MercuryFTP target.
Tue 11/04/23 1:18:27 pm - Waiting 15 seconds after cancelling...
Tue 11/04/23 1:18:27 pm - Datto Agent API request Cancel backup
Tue 11/04/23 1:18:27 pm - Cancelling running backup bb9ab0a2-a885-4961-89c4-423537130b48 ...
Tue 11/04/23 1:18:27 pm - Agent Export error occurred mid transfer (SNAPSHOT - Could not destroy snapshot.)
Tue 11/04/23 1:18:27 pm - End of backup attempt 2 of 3
Tue 11/04/23 1:18:27 pm - Agent Export error occurred mid transfer
Tue 11/04/23 1:18:25 pm - Transferring data, 0/-2 [ 0 ] Timeout Countdown 0-900
Tue 11/04/23 1:18:25 pm - Datto Agent API request Start backup
Tue 11/04/23 1:18:18 pm - Waiting 7 seconds for backup transport to setup targets
Tue 11/04/23 1:18:17 pm - Creating MercuryFTP target.
Tue 11/04/23 1:18:17 pm - Adding lun for checksum file
Tue 11/04/23 1:18:17 pm - Adding mercuryFTP lun for backup image
Tue 11/04/23 1:18:17 pm - Adding lun for checksum file
Tue 11/04/23 1:18:17 pm - Adding mercuryFTP lun for backup image
Tue 11/04/23 1:18:17 pm - Using mercuryFTP as data transport
Tue 11/04/23 1:18:17 pm - Attempting to start backup
Tue 11/04/23 1:18:17 pm - Backup transfer attempt
Tue 11/04/23 1:17:32 pm - Waiting before next attempt
Tue 11/04/23 1:17:32 pm - Leftover MercuryFTP target cleaned successfully.
Tue 11/04/23 1:17:32 pm - Removing MercuryFTP target.
Tue 11/04/23 1:17:17 pm - Waiting 15 seconds after cancelling...
Tue 11/04/23 1:17:17 pm - Datto Agent API request Cancel backup
Tue 11/04/23 1:17:17 pm - Cancelling running backup c3973025-ba1c-4ad8-a6fc-570ff537af8c ...
Tue 11/04/23 1:17:17 pm - Agent Export error occurred mid transfer (SNAPSHOT - Could not destroy snapshot.)
Tue 11/04/23 1:17:16 pm - End of backup attempt 1 of 3
Tue 11/04/23 1:17:16 pm - Agent Export error occurred mid transfer
Tue 11/04/23 1:17:14 pm - Transferring data, 0/-2 [ 0 ] Timeout Countdown 0-900
Tue 11/04/23 1:17:14 pm - Datto Agent API request Start backup
Tue 11/04/23 1:17:07 pm - Waiting 7 seconds for backup transport to setup targets
Tue 11/04/23 1:17:07 pm - Creating MercuryFTP target.
Tue 11/04/23 1:17:07 pm - Adding lun for checksum file
Tue 11/04/23 1:17:07 pm - Adding mercuryFTP lun for backup image
Tue 11/04/23 1:17:07 pm - Adding lun for checksum file
Tue 11/04/23 1:17:07 pm - Adding mercuryFTP lun for backup image
Tue 11/04/23 1:17:07 pm - Using mercuryFTP as data transport
Tue 11/04/23 1:17:07 pm - Attempting to start backup
Tue 11/04/23 1:17:07 pm - Backup transfer attempt
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Agent version
Tue 11/04/23 1:17:06 pm - Agent version
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Agent info update complete.
Tue 11/04/23 1:17:06 pm - Datto Agent API request Get host
Tue 11/04/23 1:17:06 pm - Starting agent info update
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Failed to cancel previous backup job (f42c0974-ffd5-49b8-8922-4a4770651284)
Tue 11/04/23 1:17:06 pm - Datto Agent API request Cancel backup
Tue 11/04/23 1:17:06 pm - Detected running backup job, attempting cancel (f42c0974-ffd5-49b8-8922-4a4770651284)
Tue 11/04/23 1:17:06 pm - Agent is responding on given port
Tue 11/04/23 1:17:06 pm - Agent status Agent is active port and port 25567 is open
Tue 11/04/23 1:17:06 pm - Checking connectivity for existing agent
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Cleanup found no leaked loops.
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Rolling back to snapshot
Tue 11/04/23 1:17:06 pm - Setting properties on storage
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Finished transaction stage
Tue 11/04/23 1:17:06 pm - Acquiring backup lock
Tue 11/04/23 1:17:06 pm - Committing transaction stage
Tue 11/04/23 1:17:06 pm - Backup operation started.
Tue 11/04/23 1:17:06 pm - Snapshot requested
Tue 11/04/23 1:17:05 pm - > (Completed notification. No reply.)
Tue 11/04/23 1:17:05 pm - Starting screen.
Tue 11/04/23 1:16:16 pm - Snapshot 1681229978 IntervalElapsed true, WasLastBackup false, IsLastPredictedBackup false
Tue 11/04/23 1:16:16 pm - RecoveryPoint 1681229978, Moment Now 1681236976, IsDayLater false
Tue 11/04/23 1:16:16 pm - RecoveryPoint 1681229978, NextRecoveryPoint 0, EndOfDayEpoch 1681275540

[Sir-Alex-L]

You should probably open a case with Datto directly as well if you haven't done so. That way it gets attention from both sides.

Since Ubuntu 20.04 supposed to be supported as per https://continuity.datto.com/help/Content/kb/unified-continuity/siris-alto-nas/360040893811.html and https://continuity.datto.com/help/Content/kb/unified-continuity/siris-alto-nas/KB204953800.html#System