Dedup files inaccessible after domain migration

Question

Hi guys

Migrated a deduplicated storage volume to a new Active Directory domain and now all deduplicated files are returning Access Denied errors for end users. The data itself is intact, but permissions seem broken. I suspect the issue lies within the System Volume Information folder’s security descriptors used by DataDedup. Any advanced troubleshooting steps or PowerShell commands to restore access would be greatly appreciated ?

Answer 1

Hi @Arjun Kapoor

You shouldn't try to fix this by changing the ACLs on System Volume Information. I wouldn't take ownership of or reset the permissions on the System Volume Information\Dedup folder, since that could damage the deduplication metadata.

First, confirm that the Data Deduplication feature is installed and that the migrated volume is recognized correctly:

Get-DedupVolume
Get-DedupStatus -Volume D: | Format-List *
Get-DedupMetadata -Volume D:

Also check the Deduplication Operational log for errors. Specifically, Microsoft recommends checking the dedup status, metadata, event logs, and filesystem health whenever files become inaccessible after a migration.

If the volume was moved to another server, make sure the Data Deduplication role is installed:

Install-WindowsFeature FS-Data-Deduplication

Make sure deduplication/data access is enabled for the volume.

The Dedup chunk-store ACLs should not need to change as part of the AD domain migration, since Data Deduplication lets applications and users access optimized files normally via the deduplication filter.

If either the Get-DedupStatus command or the event log shows chunk-store/metadata errors, do not make any more permission changes; instead, work from a known-good backup or raise a Microsoft support case. Microsoft expressly cautions against altering the protected Dedup metadata and advises using supported backup and restore or direct disk migration methods when dealing with deduplicated volumes.

Sharing these references with you:

Troubleshoot Windows Server Data Deduplication

Understanding Data Deduplication

Get-DedupStatus PowerShell reference

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