v2v-helper continues block copy despite "no space left on device" error during changed block copy

[kunaldevxxx]

What steps did you take and what happened?

• We initiated a VMware → target migration using vJailbreak. During the changed block copy phase, the v2v-helper pod started throwing repeated no space left on device errors while writing blocks to the local file.

• Despite these errors, the migration process continued, retried the same block multiple times, and eventually proceeded to shutdown the source VM and perform the final copy.

Relevant log excerpts:

2026/01/20 06:21:04 Failed to copy changed blocks: %!s()

2026/01/20 06:40:30 Failed to copy block: failed to write data block at offset 536868552704 to local file:
failed to write 262144 bytes at offset 536868552704: no space left on device | attempt 0

2026/01/20 06:41:30 Failed to copy block: failed to write data block at offset 536868552704 to local file:
failed to write 262144 bytes at offset 536868552704: no space left on device | attempt 1

2026/01/20 06:43:30 Failed to copy block: failed to write data block at offset 536868552704 to local file:
failed to write 262144 bytes at offset 536868552704: no space left on device | attempt 2

2026/01/20 06:47:56 Failed to copy changed blocks: %!s()
2026/01/20 06:47:56 Since full copy has completed, Retrying copy of changed blocks for disk: 2

Additional observations:

• Even after multiple write failures due to disk exhaustion, the workflow continued because of retry logic.
• The helper pod eventually proceeded to:

Shutting down source VM and performing final copy

What did you expect to happen?

Migration Should Run Successfully

Environment

Platform: vJailbreak 0.3.8

VM disks: 3 disks (Hard disk 1, Hard disk 2, Hard disk 3)

OS Family: windowsGuest

vCenter version

7.0.3.01700

Anything else you would like to add?