How to handle inconsistent names of powerpath shared disks in linux

We know that in the SAN network, because the optical fiber switch has multiple links to access the host, there will be multiple device names, that is, one storage is identified multiple times, depending on the connection link, and/dev/sd * changes to the device name for each restart of the LUN on the LINUX system of the host, we can adopt two methods. One is that a later version of linux can be configured through udev to fix the LUN device number, and the other is to use a third-party dynamic multi-path software to configure multi-path aggregation, fix the drive letter name. Here, we mainly describe the problems in the dynamic multi-path software configuration of powerpath. This problem may occur when the powerpath configuration is successfully installed, that is, the Luns corresponding to the pseudo device names recognized by the two hosts are inconsistent, as shown in the following figure:
The information obtained on the host DBTEST1 is as follows: DBTest1: /home/oracle # powermt display dev = allPseudo name = emcpowerb www.2cto.com CLARiiON ID = FCNCX093300010 [Storage Group 2] Logical device ID = login [LUN 10] state = alive; policy = BasicFailover; priority = 0; queued-IOs = 0; Owner: default = sp a, current = sp a Array failover mode: 1 ================================================ ================================================= --- ------------ Host ----------------Stor--- I/O Path -- Stats --- ### HW Path I/O Paths Interf. mode State Q-IOs Errors ====================================== ========================================================== ==== 0 qla2xxx sde SP B1 unlic alive 0 0 0 qla2xxx sdj SP A1 unlic alive 0 0 0 1 qla2xxx sdk SP B0 active alive 0 0 0 1 qla2xxx sdo SP A0 active alive 0 0 0 pseudo name = emcpoweraCLARiiON ID = FCNCX093300010 [Sto Rage Group 2] Logical device ID = 600601601EA02500F22E8FC2207AE111 [LUN 11] state = alive; policy = BasicFailover; priority = 0; queued-IOs = 0; Owner: default = sp, current = sp a Array failover mode: 1 ================================================ ========================================================= --------------- host ----------------Stor--- I/O Path -- Stats --- ### HW Path I/O Paths Interf. mode State Q-IOs Errors ====== ========================================================== ================================ 0 qla2xxx sdg SP B1 unlic alive 0 0 0 qla2xxx sdl SP A1 unlic alive 0 0 1 qla2xxx sdm SP B0 active alive 0 0 1 qla2xxx sdp SP A0 active alive 0 0 0 false name = emcpowercCLARiiON ID = FCNCX093300010 [Storage Group 2] Logical device ID = 600601601EA02500FA322E81207AE111 [LUN 1] state = alive; policy = BasicFailover; priority = 0; queued-IOs = 0; Owner: default = sp a, current = sp a Array failover mode: 1 ================================================ ========================================================= --------------- host ----------------Stor--- I/O Path -- Stats --- ### HW Path I/O Paths Interf. mode State Q-IOs Errors ====================================== ========================================================== ==== 0 qla2xxx sdc SP B1 unlic alive 0 0 0 qla2xxx sdh SP A1 unl Ic alive 0 0 1 qla2xxx sdi SP B0 active alive 0 0 1 qla2xxx sdn SP A0 active alive 0 and the information identified on host DBTEST2 is as follows: DBTest2 :~ # Powermt display dev = allPseudo do name = emcpowera www.2cto.com CLARiiON ID = FCNCX093300010 [Storage Group 2] Logical device ID = login [LUN 10] state = alive; policy = BasicFailover; priority = 0; queued-IOs = 0; Owner: default = sp a, current = sp a Array failover mode: 1 ================================================ ========================================================= --------------- host ----------------Sto R--- I/O Path -- Stats --- ### HW Path I/O Paths Interf. mode State Q-IOs Errors ====================================== ========================================================== ==== 0 qla2xxx sde SP B1 active alive 0 0 0 qla2xxx sdk SP A1 active alive 0 0 0 Pseudo name = emcpowerbCLARiiON ID = FCNCX093300010 [Storage Group 2] Logical device ID = login [LUN 11] state = alive; policy = BasicFailover; prio Rity = 0; queued-IOs = 0; Owner: default = sp a, current = sp a Array failover mode: 1 ================================================ ========================================================= --------------- host ----------------Stor--- I/O Path -- Stats --- ### HW Path I/O Paths Interf. mode State Q-IOs Errors ====================================== ========================================================== ==== 0 qla2xxx www.2cto.com sdg SP B1 active Alive 0 0 0 qla2xxx sdl SP A1 active alive 0 0 Pseudo name = emcpowercCLARiiON ID = FCNCX093300010 [Storage Group 2] Logical device ID = login [LUN 1] state = alive; policy = BasicFailover; priority = 0; queued-IOs = 0; Owner: default = sp a, current = sp a Array failover mode: 1 ================================================ ========================================================= --------------- host ------------- ---Stor--- I/O Path -- Stats --- ### HW Path I/O Paths Interf. mode State Q-IOs Errors ====================================== ========================================================== ==== 0 qla2xxx sdc SP B1 active alive 0 0 0 qla2xxx sdi SP A1 active alive 0 0 0 as shown in the above red font, we can clearly see the corresponding situation of the two host Luns as follows: DBTEST1 DBTEST2/dev/emcpowera/dev/emcpowerb/dev/emcpowera/dev/emcpowerc this time due to the installation of RAC, according to the plan, emc Powerb and emcpowerc are OCR disks and voting disks respectively, while emcpowera is a datadg disk group www.2cto.com. The following describes how to solve the problem: 1. using the management commands of powerpath software, you can change the pseudo-device names to the same ones. For details, refer to the name of DBTEST1 and make the following changes on DBTEST2: # emcpadm renamepseudo-s emcpowera-t emcpowerd # emcpadm renamepseudo-s emcpowerb-t emcpowera # emcpadm renamepseudo-s emcpowerd-t emcpowerb Update Configuration, restart the host to check whether the two ends are consistent. 2. in addition, we can also use the following method, that is, to keep the pseudo device name unchanged and use Block devices, DBTEST1 DBTEST2/dev/raw/raw3/dev/emcpowera/dev/emcpowerb/dev/raw/raw2/dev/emcpowerb/dev/emcpowera/dev /raw/raw1/dev/emcpowerc. In this way, you only need to specify the raw device name for each host during RAC installation. Author: marvelyu