Failed to collect disk files location data. Timeout exceeded.

Investigating Slow Disk File Location Collection

The performance of the disk file location collection is directly tied to the Map Disk Region events that occur within the vSphere environment, both their quantity and how quickly they are completed. Each Map Disk Region task maps the beginning and end point of a contiguous section of blocks on the storage associated with the VMDK. Therefore, if a snapshot is present before the job begins or the VMDK is heavily fragmented, the number of Map Disk Region tasks increases.

The following are likely to increase the number of Map Disk Region tasks that will occur, or how fast they are completed:

• A snapshot exists on the VM prior to the job starting.
  
  Processing a VM with a snapshot present is fully supported; however, that snapshot's presence will impact the "Collecting disk file location" stage of any BfSS job.
•  Fragmentation of the VMDK on the datastore (not guest level).
• Issues with the storage underlying the datastore.

Adjusting Timeout

If, after investigating the list of potential causes above, the timeout continues to cause the task to fail, you may choose to change the timeout by creating and adjusting the registry value below on the Veeam Backup Server.

Key Location: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
Value Name: SanCollectDiskMappingTimeoutSec
Value Type: DWORD (32-Bit) Value
Value Data (Dec.): 10800 [default]

Notes:

• No reboot or service restart is required; the new timeout value will be used during the next job run.
• The value data is in seconds. The default value is 10800, which is equal to 3 hours.