Will EMC PowerPath affect existing SSA and SCSI disk names on AIX?

[bingS4]

I'm installing EMC PowerPath on AIX 5.2 for the first time to work with out CLARiiON CX3-20c. I have a large number of existing SSA and a couple SCSI disks on the host.

Will installing EMC PowerPath affect how those disks are accessed/named in any way? My hunch is "no", but I've been unable to locate any explicit information about them. The manual says to varyoff any volume groups on "storage-system hdisk devices". I assume this means SAN storage, and that my SSA hdisks will not be converted into hdiskpower devices, but I need to make sure before I do this.

Any help, please?

Thanks!

 

[Korwin]

It shouldn't touch or change any hdisk names. It will add/change hdiskpowerXX when it discovers redundant hdisks pointing to the same EMC lun.

PowerPath will find these redundant hdisks (paths) and add a single hdiskpowerX for each lun. The hdiskpower is what you will use for your volume groups etc.

A command or 2 to commit to memory:
powermt display
(will show you a list of HBAs and how many LUNS/Paths on each)
powermt display dev=all
(shows a list of luns with the backend clariion name, and the local hdisk name, as well as the hdiskpower name).

Example:

->sudo powermt display dev=all
Pseudo name=hdiskpower1
CLARiiON ID=APM00050200571 [R6KWMSTR_SG]
Logical device ID=60060160370313000EAE471445F2DB11 [LUN 83]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP B, current=SP B
==============================================================================
---------------- Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
0 fscsi0 hdisk15 SP A0 active alive 0 0
0 fscsi0 hdisk18 SP A3 active alive 0 0
0 fscsi0 hdisk21 SP B0 active alive 0 0
0 fscsi0 hdisk24 SP B2 active alive 0 0

Pseudo name=hdiskpower0
CLARiiON ID=APM00050200571 [R6KWMSTR_SG]
Logical device ID=6006016037031300564BA52645F2DB11 [LUN 95]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP A, current=SP A
==============================================================================
---------------- Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
0 fscsi0 hdisk16 SP A0 active alive 0 0
0 fscsi0 hdisk19 SP A3 active alive 0 0
0 fscsi0 hdisk22 SP B0 active alive 0 0
0 fscsi0 hdisk25 SP B2 active alive 0 0



This host only has 1 HBA since its a dev box. Production boxes would 2 here. As you can hdisk 16, 19, 22 and 25 are all really the same LUN, and powerpath groups them together to become hdiskpower0

 

[bingS4]

Thanks for the reply! I installed and everything worked great.