Error: STC failure occurred mid transfer - Too small destination volume

Topic

This article explains the cause and solution of the error:

STC failure occurred mid transfer - Too small destination volume: must be ########## sectors, is ##########.

IMPORTANT  Shadowsnap is now End of Support. Please migrate from the shadowsnap agent to the latest compatible Datto Windows Agent or Agentless solution. For information on this process, please refer to: How to move from ShadowSnap to the Datto Windows Agent

Environment

  • Datto SIRIS
  • Datto ALTO

Description

This error happens when disks have been recently re-sized, and the sparse image does not have enough space.

Resolution

  1. Ensure the latest version of DWA is installed.
  2. If the backups are unencrypted, force a differential merge. If the backups are encrypted, proceed straight to Step 3.
  3. Delete the sparse image from the web interface of the device.
    • Go to the web interface for the device.
    • Under the Protect tab, select Configure Agent Settings.
    • Select Advanced Settings followed by Volume Level Backup Control.
    • Now, delete the volume that was recently re-sized. There will be a warning: click OK to continue.
  4. Delete the agent's full sparse image (i.e: all the volumes). In the web interface, select Advanced Options for the agent, and select Destroy Live Dataset. This will delete the full image of the agent, but have the same functionality with the old snapshots and the old live dataset.
  5. Take a new backup. This will be a full base image and will reflect the size of the current dataset.

If this issue persists, contact Datto Technical Support for further assistance.