PowerProtect Data Manager: Intermittent Data Domain Discovery Failures With ADS0005

• Periodic Data Domain discovery jobs fails intermittently
• Error Code:  ADS0005
  • PPDM error codes represent a broad issue category and can map to numerous possible root causes. Ensure the log error matches the example shown below.
• Full Discovery completes without error
• The intermittent failure can often be at the same time every day and eventual affect all periodic discoveries for that DD
• Data Domain status in the PPDM UI remains READY / OPERATIONAL_RUNNING and backups continue without impact.

Discovery System Job intermittently fails with error like below, when the password and credentials are correct.

Unable to discover protection storage PowerProtect Data Domain System with address <DD_HOSTNAME> because of ResourceException: Error while executing /rest/v1.0/dd-systems/8f72c1a4b9e63dfe%3A2b7c914deaf50831/mtreescode: 5028 statusCode: 500 Error: **** The filesystem is not responding..,errorCode=<null>,messageID=ADS0005,remediation=Check the connection between PowerProtect Data Manager and the protection storage system. Verify that the provided credentials are valid. Ensure that the password is not expired. Start a manual discovery to discover the protection storage system, or wait for PowerProtect Data Manager to perform the next scheduled discovery. If the issue persists, contact Dell Customer Support.

or

Unable to discover protection storage PowerProtect Data Domain System with address 192.168.00.000 because of ConnectException: Connection timed out.,remediation=Check the connection between PowerProtect Data Manager and the protection storage system. Verify that the provided credentials are valid. Ensure that the password is not expired. Start a manual discovery to discover the protection storage system, or wait for PowerProtect Data Manager to perform the next scheduled discovery. If the issue persists, contact Dell Customer Support.

The discovery‑service uses an HTTP client (DataDomainRestClient) that maintains a connection pool to the Data Domain management interface. Over time, stale or hung connections accumulate, exhausting the pool. When the pool is exhausted, new TCP SYN packets to the DD management IP receive no response, resulting in ConnectException: Connection timed out errors and the ADS0005 critical alert.

• Stale connections are not reclaimed due to missing timeout handling.
• Network path sensitivity on the dedicated management interface can exacerbate the problem.

Contributing Factors

• Long‑running discovery cycles without periodic pool cleanup.
• Management interface located on a different subnet from the PPDM appliance.
• Absence of retry logic improvements in versions prior to 20.3.

Upgrade to PPDM 20.3 or Later

• Upgrade to PPDM 20.3 or later. Download the release from the PowerProtect Data Manager Drivers & Downloads page. This release fixes the HTTP connection-pool exhaustion issue.
• After upgrading, monitor periodic discovery cycles. Confirm they complete without ADS0005 alerts.

Restart the Discovery Service

If the upgrade cannot be applied immediately:

• Log in to the PPDM appliance over SSH.
• Restart the discovery service to clear the exhausted connection pool:

  discovery-service restart

• Allow a few minutes for the service to fully restart. The PPDM UI may show 503 errors during this time. This is expected.
• Monitor the next discovery cycle. Confirm it completes without ADS0005 alerts.