Cause Analysis
(1) When a heterogeneous LUN is connected, I/Os are sent to the remote end to query reservation information. The I/O fails to be read.
(2) If the remote reservation information fails to be read, the registration reservation failure event is reported to the upper-layer ADM module.
(3) After receiving the registration reservation failure event, ADM reports an alarm indicating that the path from the local storage array to the heterogeneous storage array fails to be registered.
(4) At 23:56:39 on July 16, 2020, LUNs were scanned again.
(5) After LUNs are scanned again, I/Os are sent to the remote end to query reservation information. The query is successful.
(6) Although the local storage array successfully registers the path to the heterogeneous storage array after LUNs are scanned again, the alarm suppression is not cleared because the recovery event of the successful path registration is not sent to the BDM_ADM module.
Root Cause
1. When a heterogeneous LUN is connected, I/Os are sent to the remote end to query reservation information. The I/O fails and the remote reservation information fails to be read. According to the recurrence test in the lab, there is no risk of the query failure when the NETAPP FAS8020 is in the NO_RESERVE disk mode on the live network.
2. When the NETAPP FAS8020 has no reservation, an I/O failure message is returned when the reservation information is queried (the I/O should be successful). After the LUN scanning operation is triggered again, the reservation information I/O success message is returned.
Solution
(1) When a heterogeneous LUN is connected, an I/O request is sent to the remote end to query reservation information. The I/O fails and the remote reservation information fails to be read. In this case, alarm 0xF000B010B is sent. You can handle the alarm according to the alarm handling suggestions.
(2) Trigger LUN scanning again. After the reservation information of the remote LUN of the NetApp is read, the 0xF000B010B alarm is cleared.
