Find LUN ID's with MPIO

[markuscj]

We are in the process of moving from SDD to MPIO to prepare for new XIV storage (we currently have ESS and DS8000).

With SDD we could query the vpaths for the LUN using lsvpcfg|grep vpathx

Using standard MPIO on AIX 5.3.8 the best I have found so far is getting it from the unique_id field using lsattr -El hdiskx - however the LUN ID appears differently depending on whether it's ESS or DS and is not very clear.

Is there an easier way?

TIA

 

[p5wizard]

The LUN id is hidden somewhere in the hardware location code of the devices for ESS and DS8k. Not sure about XIV LUNs.

lscfg -l hdiskX

Then look at the last part of the location code. It is something like -40xx40yy...

LUN id should be xxyy.

The part before the dash is the WWNN of the primary host-adapter of the storage box.

[aside]
Did you thoroughly test XIV (perf, fault-tolerance, upgradeability...) against ESS and DS8k. What were your findings?
[/aside]

HTH,

p5wizard

 

[markuscj]

Thanks, I can see the LUN can be identified by that as well - still not as clear as the lsvpcfg command though!!

ESS looks easy enough, I have seperated the LUN ID with a *

U787A.001.DPM035R-P1-C3-T1-W5005076300CCABF2L5*00D*000000000000 MPIO Other FC SCSI Disk Drive (00D)

DS is

U0.1-P1-I5/Q1-W500507630503429F-L40*91*40*0F*00000000 MPIO Other FC SCSI Disk Drive (910F)

We don't have the XIV storage yet, we should be getting a 'proof of concept' box within the next month, we will be testing performance vs ESS/DS then. If we go with it our ESS storage will be retired and we will use DS/XIV.

 

[p5wizard]

[OffTopic]
You should have installed SDDPCM on top of MPIO driver. That is a PathControlModule specific for ESS/DS6k/DS8k. Now you just have MPIO with AIXPCM, which only does basic support for MPIO (path failover only). SDDPCM has LoadBalancing also.

Keep us informed of your XIV challenge.
1TB 7kRPM SATA disks vs 146GB 15kRPM FC disks - Hmm... difficult choice.
[/OffTopic]


HTH,

p5wizard

 

[markuscj]

I looked at SDDPCM, according to IBM only the native MPIO works with XIV right now, I'm sure that will change as XIV becomes more 'standard'

 

[p5wizard]

IMHO you can have multiple PCMs plugging in to MPIO. I don't see why you shouldn't use SDDPCM for your ESS/DS LUNs and the more basic AIXPCM for the XIV LUNs. I'd try that out on a test box as soon as you get your hands on the POC XIV server.


HTH,

p5wizard

 

[sbix]

p5wizard, not only SDDPCM gives something like the "load balancing" feature.
The MPIO normally supports also "round robin" management for multiple paths.
I have Hitachi disks which are normally configured with "algorythm=fail_over"by cfgmgr.
I wrote a script to "chdev" them to work in "round_robin fashion" (algorytm=round_robin") and it works.
The load_balancing feature is just a little more efficient but only in some case.

Regards,
sbix

 

[markuscj]

I set up my mpio disks with

algorithm - round_robin
reserve_policy-no_reserve

I guess this is correct, I had not even looked into MPIO until last week!

I have now written a script to find the LUN numbers as well.

@p5wizard - we could have just kept our DS boxes on sdd, but the decision was made to keep them all generic (if we do go XIV), so all OS upgrades etc will be the same - i.e. we don't have to upgrade sdd when we go up an AIX level.

 

[sbix]

markuscj, those settings are the same of mine and they are correct.
For what concerning the LUN id, if you exec the command lsattr -El hdiskx |awk '/^lun_id/{print $2}'
you SHOULD have something more or less significant

 

[markuscj]

Thanks sbix

I have written a script now to get it from the unique_id - the problem was the LUN ID would appear differently depending on whether it was ESS or DS.

The storage unit identifer appears in the unique_id field as well, so my script looks for that and does one thing for ESS and another for DS.

Got there in the end, but I miss my lsvpcfg command!!!