What foreground verification is

Foreground verification is a user-initiated process that checks if all expected object data exists on a Storage Node. Foreground verification is used to verify the integrity of a storage device.

Foreground verification is a faster alternative to background verification that checks the existence but not the integrity of object data on a Storage Node. If foreground verification finds that many items are missing, it may indicate that there is an issue with all or part of a storage device associated with the Storage Node. If foreground verification finds issues when verifying erasure coded objects, you must perform a recovery procedure for any affected storage volumes.

Foreground verification checks both replicated object data and erasure coded object data. If foreground verification finds a missing copy of object data, it automatically attempts to replace it.

If a copy of replicated object data is found to be missing, the StorageGRID Webscale system automatically attempts to replace it from copies stored elsewhere in the system. The Storage Node runs 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 missing object no longer exists at the expected location. A new copy is generated and placed to satisfy the system's active ILM policy. This new copy may not be placed in the same location that the missing copy was stored.

If a fragment of a copy of an erasure coded object is found to be missing, the StorageGRID Webscale system automatically attempts to rebuild the missing fragment in place on the same Storage Node using the remaining fragments. If the missing fragment cannot be rebuilt, the Corrupt Copies Detected (ECOR) attribute is incremented by one. ILM then attempts to find another copy of the object which it can use to generate a new erasure coded copy.

If no other copies of a missing replicated object or a corrupted erasure coded object can be found in the grid, the LOST (Lost Objects) alarm is triggered.

If foreground verification identifies an issue with erasure coding on a storage volume, the foreground verification grid task pauses with an error message that identifies the volume that is affected.