What background verification is

The background verification process automatically and continuously checks Storage Nodes for corrupt copies of object data, and automatically attempts to repair any issues that it finds.

Background verification checks the integrity of both replicated object data and erasure coded object data.

If background verification detects that a copy of replicated object data is corrupt, that corrupt copy is removed from its location and quarantined elsewhere on the Storage Node. The Storage Node's LDR service then sends a request to the DDS service to create a new uncorrupted copy. The DDS service fulfills this request by running an existing copy through an ILM evaluation, which will determine that the current ILM policy is no longer being met for this object because the corrupt object no longer exists at the expected location. A new copy is generated and placed to satisfy the system's active ILM policy, which may not be in the same location that the corrupt copy was stored. Corrupt object data is quarantined rather than deleted from the system, so that it can still be accessed. For more information on accessing quarantined object data, contact technical support.

If background verification detects that a fragment of erasure coded object data is corrupt, the StorageGRID Webscale system automatically attempts to rebuild the missing fragment in place on the same Storage Node using the remaining fragments of that copy. If the corrupted fragment cannot be rebuilt, the Corrupt Copies Detected (ECOR) attribute is incremented by one, and an attempt is made to retrieve another copy of the object. If retrieval is successful, an ILM evaluation is performed to create a replacement copy of the erasure coded object data.

If background verification cannot replace a corrupted object because it cannot locate another copy , the LOST (Lost Objects) alarm is triggered.

Background verification runs at a continuous rate that is designed not to interfere with ordinary system activities. Background verification cannot be stopped. However you can increase the background verification rate to more quickly verify the contents of a Storage Node if you suspect a problem.

Background verification does not run on Archive Nodes.