Installing powerpath and changing the emc pseudo device name

EMC powerpath is one of the best multipathing software that is used on the servers and not only it is stable but it is very easy to use, today i would like to show how to install it and to change the pseudo device name, sometimes when you are working on server where the luns are shared you want the device name to be same so that you can find them easily and sometime make your troubleshooting easier.

First thing you need is a powerlink.emc.com account to download the EMC powerpath which is supported for your Operating system

[root@linux01 ~]# rpm -ivh EMC/EMCPower.LINUX-5.6.0.00.00-143.RHEL5.x86_64.rpm
   Preparing...                         ########################################### [100%]
  1:EMCpower.LINUX         ########################################### [100%]
All trademarks used herein are the property of their respective owners.
NOTE:License registration is not required to manage the CLARiiON AX series array.

After installing the powerpath package next thing you need to license the software to use the feature of it.

[root@linux01 ~]# emcpreg -list
There are no license keys now registered.

[root@linux01 ~]# emcpreg -add XXXX-XXXX-XXXX-XXXX-XXXX-XXXX
1 key(s) successfully added.

[root@linux01 ~]# emcpreg -list
Key XXXX-XXXX-XXXX-XXXX-XXXX-XXXX
  Product: PowerPath
  Capabilities: All

Start the service and then if you have done the zoning then check for any new luns which are visible on the host HBA's
[root@linux01 ~]# /etc/init.d/PowerPath start
Starting PowerPath:  done

[root@linux01 ~]# powermt check

[root@linux01 ~]# powermt display dev=all
Pseudo name=emcpowerb
CLARiiON ID=CKM00103100530 [Test-SG]
Logical device ID=600601604D3827004E67486CA534E211 [LUN 1]
state=alive; policy=CLAROpt; 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
==============================================================================
   2 qla2xxx                  sdc       SP A1     active  alive       0      0
   2 qla2xxx                  sdf       SP B0     active  alive       0      0
   3 qla2xxx                  sdh       SP A0     active  alive       0      0
   3 qla2xxx                  sdj       SP B1     active  alive       0      0


At time you want the luns which are shared across the servers to have the same pseudo name so that you can recognize them in case you want to increase the size or sometime for troubleshooting.

[root@linux01 ~]# emcpadm getusedpseudos
PowerPath pseudo device names in use:
Pseudo Device Name      Major# Minor#
        emcpowera         120      0
        emcpowerb         120     16

After finding the all the pseudo devices that you are using find the next available pseudo device which you can use.

[root@linux01 ~]# emcpadm getfreepseudos
Next free pseudo device name(s) from emcpowera are:
Pseudo Device Name      Major# Minor#
        emcpowerc         120     32

Now lets rename the device and check if its reflecting
[root@linux01 ~]# emcpadm renamepseudo -s emcpowera -t emcpowerc

[root@linux01 ~]# emcpadm getusedpseudos
PowerPath pseudo device names in use:

Pseudo Device Name      Major# Minor#
        emcpowerc         120      0
        emcpowerb         120     16