Securepath 4.0C - MSA1000 - FCA2101 - alternate paths are not detected

[Karthik S S]

Hi,

We have the following configuration.

- MSA1000 - Single Controller with 2 * 2/8 internal SAN Switches *(Cascaded)

- 2 * DL580 with 4 * FCA2101 FC HBAs

- DL580s are booting from SAN (MSA Luns)

- Securepath 4.0C is installed

- MSA1000 and FCA2101 are upgraded to latest firmware revision.


Problem:
When I do spmgr display I can see only one path to the MSA LUNs even though there are 4 FC Cards present on the system.

Before installing securepath I was able to see 4 instances of each LUN from diskmanagement.

Pl. check the attached file.

What could be the problem?

Thanks,
Karthik S S

Uwe: I opened a separate thread to avoid confusion.

[Karthik S S]

Note:

Using Selective Storage Presentation I have made the boot LUNs visible through only one FC HBA of their respective servers.

I have created one more test LUN and presented them to all the FC adapters of both DL580s.

No zoning is configured on the switch.

Thanks,
Karthik S S

[Uwe Zessin]

Hello Karthik,
I have set up a server (with 2x FCA2214DC) with two EVAs. One adapter port can access one LUN per EVA. I have also configured a second port to have access to the first EVA, too. As you can see from the attachment I have four paths to drive E: (both adapter ports hit the same EVA controller ports) and two paths to drive F:.

If you snoop around in RAIDISK.SYS you will see that the filter driver contains several array names. It is possible that the driver deliberatly prevents multiple paths to be seen. The only one who can really answer this question is HP.

[Karthik S S]

Hi Uwe,

Thanks for the Info. In fact even I have tried Securepath with a VA7410 - Single controller and a system with 2 FC HBAs and it used to work. Wonder why it doesn't with the MSA1000.

Thanks,
Karthik S S

[Uwe Zessin]

Karthik,
for the VA7xxx you are really using the AutoPath software. It has only recently merged into the SecurePath software.

Please note that the VA7xxx series presents the LUNs in a different way than the EVA.

[Karthik S S]

Yeah .. u r right. I meant autopath utility only.

Thanks,
Karthik S S

[Doug de Werd]

the problem is that you only have a single controller in the MSA1000. This is nto a supproted ocnfiguration. If you are going to have 2 HBA's per server running SecurePath, you must also have 2 RAID controllers in the MSA1000. Also, it is not supported to cascade the 2 internal switches within a single MSA1000. I would recommend getting another MSA1000 RAID controler, and then you would have a fully redundant setup. However, even if you do this, keep in mind that the MSA1000 RAID Controllers are active/passive, so even though you will have 2 paths per server to the storage, only one can be active at any given time.

Thanks,
Doug

[Karthik S S]

Hi Doug,

Thanks for the Info. But is there any supporting Doc. that claims having one controller is not a supported configuration? Because, I need to convince my management :-( ..

I found a few but not very particular about the controllers,

http://www.precisiongroup.com/enterpriseModularArraysan1000QuickSpecs.htm


Thanks,
Karthik S S

[Uwe Zessin]

Karthik,
single-controller configurations are supported. The problem is that you want to attach multiple fibre channel adapters of a single server to the same controller port, perhaps even accessing the same LUN.

I don't see a technical problem here - it should not matter if the adapters are in one server or in different servers. I rather guess that is a limitation that Secure Path enforces.

The link you gave referenced an old specification - here is a better one:
http://h18000.www1.hp.com/products/storageworks/msa1000/specifications.html

[Doug de Werd · Accepted solution]

the issue is not with single controllers - they are absolutely supported. The issue is with how the MSA1000 handles it - and it relates to the fact that the MSA1000 RAID Controllers are active/passive. This is why it is sometimes confusing, especially if you have experience with other storage like EVA, MA8, VA, etc. (things like transparent/multi-bus failover)

The best way to think about how it works for an MSA1000 is that you have 2 choices, and that's it.

Choice #1 = single path. This means single path ALL the way through. One HBA per server, one SAN switch, and one MSA1000 controller, no SecurePath

Choice #2 = dual path. This means dual components ALL the way through. Two HBAs per server, two SAN switches, two MSA1000 controllers, and does require SecurePath.

There are no in-between configurations, which is what you have. You either have a single of everything, or a double of everything, but you cannot have singles of some stuff and doubles of others. Another way to think about it is that the MSA1000 does not support transparent controller failover mode (like HSG80).

Hope this helps,
Doug

[Karthik S S]

Thanks you Doug. That helped me a lot. Just noticed that your head gear has changed to Graduate cap :-) ... Congratulations ..!!

Thanks,
Karthik S S