Method used to safely delete a LUN mapping from an AIX application server

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Perform the following operations to delete a LUN mapping from an AIX application server:
On the storage device side, delete the LUN mapping with the AIX application server.
On the AIX application server side, run rmdev -dl diskName to delete the virtual disk of the mapped LUN.
For example, you can run rmdev -dl disk3 to delete the virtual disk disk3.
Note:
If the virtual disk is not deleted and a new LUN is mapped to the AIX application server, a fault occurs, indicating that the virtual disk path is missing. Rectify the fault as follows:
Unmount the file systems of the original LUN and the newly mapped LUN.
Close the volume group of the newly mapped LUN.
Delete the virtual disks of the original LUN and the newly mapped LUN.
Run cfgmgr to re-scan for disks.

Other related questions:
Why does an application server lose all the LUNs mapped to it after being configured with the 360 Safe software?
The cause is that the 360 Safe software disables the iSCSI services. You can manually restart the iSCSI services and scan for the disks, and then the LUNs mapped to the application server can be detected again. The 360 Safe software disables the iSCSI services; therefore, you are advised to uninstall the 360 Safe software from the application server, and install another security software.

For V3 series unified storage V300R001, how can I query the mapping relationship between LUNs and hosts?
For V3 series unified storage systems V300R001, you can obtain the information about LUNs and its mapped hosts from the mapping view. You can identify the corresponding relationship between storage systems' hosts and their connected application servers in the live network through parameters such as host names and host operating systems. You are advised to use a host name that is easy for you to recognize the host's corresponding application server. For details about how to view mapping views, see Viewing Mapping View Information.

Method to query the mapping relationship between LUNs and hosts on T series V100R005 devices
On the T series V100R005 storage system, you can view information about mapped LUNs by checking the host information. You can identify the corresponding relationship between storage systems' hosts and their connected application servers in the live network through parameters such as host names and host operating systems. You are advised to use a host name that is easy for you to recognize the host's corresponding application server. For details about how to check the host information, see Viewing Host Information.

Method used to map a LUN larger than 2 TB to a server
The storage system can create a LUN larger than 2 TB. Before a LUN larger than 2 TB is mapped to the host, check whether the host operating system can identify the LUN.

Method used to check newly mapped LUNs on the server not installed with the multipathing software
Method used to check newly mapped LUNs on the server not installed with the multipathing software: 1. Log in to the application server. 2. Run cd /sys/class/scsi_host/ to enter the /sys/class/scsi_host/ directory. # cd /sys/class/scsi_host/ 3. Run ls to check the HBA card port in the /sys/class/scsi_host/ directory (for example, host0, host1, and host2). # ls host0 host1 host2 host3 host4 host5 host6 host7 host8 4. Run echo "- - -" > /sys/class/scsi_host/host*/scan to scan for disk devices. host* is an HBA card port. The LUN mapped to the HBA card port host2 is used as an example. # echo "- - -" > /sys/class/scsi_host/host2/scan 5. Run lsscsi to check LUN s newly mapped to the server. # lsscsi [0:0:0:0] cd/dvd hp DVD D DS8D3SH HHE7 /dev/sr0 [2:0:0:0] disk HUASY S5500T 2105 - [2:0:0:1] disk HUASY S5500T 2105 - [2:0:0:2] disk HUASY S5500T 2105 - [2:0:0:3] disk HUASY S5500T 2105 - [2:0:0:4] disk HUASY S5500T 2105 - [2:0:0:5] disk HUASY S5500T 2105 - [2:0:0:6] disk HUASY S5500T 2105 - [2:0:0:7] disk HUASY S5500T 2105 - [2:0:0:8] disk HUASY S5500T 2105 - [2:0:1:0] disk HUASY S5500T 2105 - [2:0:1:1] disk HUASY S5500T 2105 - [2:0:1:2] disk HUASY S5500T 2105 - [2:0:1:3] disk HUASY S5500T 2105 - [2:0:1:4] disk HUASY S5500T 2105 - [2:0:1:5] disk HUASY S5500T 2105 - [2:0:1:6] disk HUASY S5500T 2105 - [2:0:1:7] disk HUASY S5500T 2105 - [2:0:1:8] disk HUASY S5500T 2105 - [3:0:0:0] disk HUASY S5500T 2105 - [3:0:0:1] disk HUASY S5500T 2105 - [3:0:0:2] disk HUASY S5500T 2105 - [3:0:0:3] disk HUASY S5500T 2105 - [3:0:0:4] disk HUASY S5500T 2105 - [3:0:0:5] disk HUASY S5500T 2105 - [3:0:0:6] disk HUASY S5500T 2105 - [3:0:0:7] disk HUASY S5500T 2105 - [3:0:0:8] disk HUASY S5500T 2105 - [4:0:0:0] disk up updisk 2105 /dev/sda [4:0:0:1] disk up updisk 2105 /dev/sdb [4:0:0:2] disk up updisk 2105 /dev/sdc [4:0:0:3] disk up updisk 2105 /dev/sdd [4:0:0:4] disk up updisk 2105 /dev/sde [4:0:0:5] disk up updisk 2105 /dev/sdf [4:0:0:6] disk up updisk 2105 /dev/sdg [4:0:0:7] disk up updisk 2105 /dev/sdh [4:0:0:8] disk up updisk 2105 /dev/sdi

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