PowerProtect Data Manager: TSDM backup "Performing LWD sync" step fails with "Operation timed out"

The TSDM Backups session fails and shows:

YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]   "Status": {
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     "State": "Failure",
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     "Description": "Backup is unsuccessful:  The error cannot be retried.  Unable to successfully complete SDM Delta Sync operation.  Unsuccessful after 2 attempts over 3h10m20.538739708s.  The vCenter task for 'SDM Snapshot Sync Delta' completed with state 'error'.  Operation timed out.",
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     "Progress": 0,
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     "Error": {
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       "Text": "The error cannot be retried.  Unable to successfully complete SDM Delta Sync operation.  Unsuccessful after 2 attempts over 3h10m20.538739708s.  The vCenter task for 'SDM Snapshot Sync Delta' completed with state 'error'.  Operation timed out.",
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       "Code": 0,
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       "Classifications": [
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]         "VCenter"
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       ],
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       "Retryable": false,
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       "Remedy": null
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     },
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     "Warnings": [
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]       "The vCenter task for 'Cancel LWD Snapshot' completed with state 'error':  DPD Sync in progress"
YYYY-MM-DD HH:MM:SS INFO:   [af8c13ef3a367775;a359912acfd49a10]     ],

The underlying storage becomes unresponsive to the DPD service, which causes the SDM Delta Sync operation to time out. By design, the DPD service does not expose a configurable timeout for storage API calls. One or more of the following conditions can trigger the unresponsiveness:

• A faulted Host Bus Adapter (HBA) on an ESXi host
• An overloaded HBA that cannot process requests in time.
• Other DPD infrastructure issues affecting storage communication.

Investigate and resolve the underlying storage issue in the environment. Follow these steps:

1. Check HBA health — Open the vSphere Client, browse to the affected ESXi host, and verify that no HBA shows a faulted or degraded state in the storage adapter list.
2. Validate storage connectivity — Confirm that the ESXi host can communicate with the storage by reviewing datastore accessibility and running connectivity tests (for example, esxcli storage core path list).
3. Reduce HBA load — If the HBA is overloaded, redistribute VM workloads across additional HBAs or hosts in the vSphere cluster to lower I/O pressure.
4. Investigate DPD infrastructure — Review DPD service logs and the broader data‑protection infrastructure for errors, resource contention, or misconfigurations that may contribute to storage timeouts.
5. Restart DPD and TSDM services — After resolving the root cause, restart the DPD and TSDM services on the affected ESXi host to restore normal backup operations and re‑enable vMotion for the affected VMs.
6. Retry the backup — Initiate a new TSDM backup session for the previously failed VMs and confirm that the session completes successfully.
7. Contact Dell Support — If the issue persists after completing the steps above, contact Dell Support for further investigation.