GMD Limitations

GMD can recover from most network failures, but in particular cases, there can be problems:

If a sending process crashes before an outgoing message can be completely saved to the GMD area, the message cannot be recovered.

If a receiving process crashes after processing a message but before the highest sequence number can be updated in the GMD area, the message might be processed twice.

Mixing GMD and message priorities can cause the highest sequence number in the GMD area to be updated in non-sequential order. If the receiving process crashes while processing messages in non-sequential order, the resent messages might be skipped.

Though unlikely, these conditions can occur if a node or disk crashes while a message is being written or while sequence numbers are being updated.