Solution if the host fails to detect LUNs

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Solution if the host fails to detect LUNs:
Determine the connection mode at the front end. If the Fibre Channel switch is connected, check whether the switch mode has been configured.
If the front end uses the Fibre Channel switch, check with the customer that the switch has been correctly configured with zones and assign the storage system and the host to the same zone. If the port WWN is bonded during zone division, check whether the port binding is correct. Alternatively, use optical fibers to directly connect the storage system to the switch and re-scan for LUNs.

Other related questions:
Solution if LUNs fail to be detected after the host initiator or HBA card is changed
Solution if LUNs fail to be detected after the host initiator or HBA card is changed: 1. Description: What can I do if LUNs fail to be detected after the host initiator or HBA card is changed? a. The iSCSI Initiator Node Name value of the host is changed. b. The HBA card (Fibre Channel or SAS) of the host is replaced. 2. Solution: a. For the iSCSI connection in the front end, change the name of the host initiator to the changed iSCSI Initiator Node Name value. b. For the Fibre Channel or SAS connection in the front end, add the WWN of the current host's port to the storage array.

Online expansion methods when LUNs cannot be detected on the host of an OceanStor V3 storage system
SmartThin provides two methods for online expansion: storage pool expansion and thin LUN expansion.

The application server connected to the OceanStor V3 storage system fails to detect LUNs
Refer to Revelations of Troublesolving cases on the right.

Method used to detect new LUNs on the host of OceanStor T/V3 storage systems
If Huawei UltraPath is installed on the host, run the hot_add command to scan for disks. The existing services will not be affected. If the multipathing software is not installed, use the iSCSI network and restart the iSCSI service. If the Fibre Channel network is used, restart the server.

Problem and solution when some LUNs fail to be mapped when LUNs are mapped in batch
After LUN mappings are canceled in batch in a storage system, the LUNs generated on a host still exist. As a result, the storage system returns "Unmapped" with error code 0x05/0x25/0x00 due to I/Os sent using these LUNs. The interface protocol indicates that the error code performs a LUN switchover but the storage system uses a system lock for the LUN switchover. As a result, LUN mapping fails because no system lock can be obtained. To solve this problem, map the LUNs again. Then check whether the number of LUNs that are successfully mapped is correct.

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