ESX Multipath problem

Question

Hi,

We have CX3-10 directly connected (no FC switch) to 2 esx servers. Each esx server has 2 HBAs. One of the HBA on either esx is connected to SPA port and SPB port.

But on ESX server HBAs can see only one target. I have ArrayCommpath is "Enabled" and Failovermode is set to "1". I remember when initially i set it up by manually registering the hosts each HBA was able to see both the targets but not any more. We never changed the failover settings on esx, they are still on MRU. Only thing i can think of is we installed navihost agent on our esx servers and it is great as i can see the canonical addressings on SAN and that for sure is helpful.

Any help on this will be really appreciated.

Thanks

ovivier · Answer

Hi technicolor,

Well, failover parameters seems to be ok.

Can you provide us the result of "esxcfg-mpath -l" ? Then we could check if all targets are seen and in which state.
Please provide also the result of "esxcfg-rescan" on each HBA.

In Navisphere check also if you have enabled all paths. To do that:
- enable engineering mode with [password deleted]
- right clic on the Storage Group -> Properties -> Hosts Tab -> Advanced
- here you should have 4 lines enabled for each ESX server

Hope this helps
Olivier

Message was edited by: 3CsForumModerator

dynamox · Answer

unless you are using dual port HBAs i don't see how you are going to see multiple targets. Since you are not connected to the switch and connecting directly. One HBA is connected to either SPA or SPB, hence one target per HBA.

YDroid · Answer

Well we are using single port HBAs, but we remember to see paths to both the targets on esx MUI before. It just disappeared. Changes related to SAN that may or may not effect this that i can think of are, FLARE code upgrade and installation of navihost agent.

Also another calarification, doesnt both the SPs communicate via CMI-BUS and incase of SP failure LUNs will tresspass? If yes to this wouldnt same happen incase of HBA failure?

dynamox · Answer

i still don't see how you could see two targets per HBA if the HBA is connected directly to either SPA or SPB.

As far as i know LUN trespassing is initiated by the host's failover software. So if host is zoned this way:

HBA1 - SPA0, SPB0
HBA2 - SPA1, SPB1

if SPA goes unavailable and the host has at least PowerPath light, it will mark paths on HBA1 and HBA2 to SPA failed, initiate trespass to SPB and use either HBA1 or HBA2 to access that LUN on SPB. If you have fully license PowePath ..it will use both HBA1 and HBA2 to access that LUN on SPB.

RRR · Answer

Changes related to SAN that may or may not effect this that i can think of are, FLARE code upgrade and installation of navihost agent.

Uhm, i'm confused, first you state you have hosts directly connected and now you say you changed something on the SAN. What SAN ? You said you're directly connected to the storage ! If you do have a SAN I'd say: check zoning, perhaps for each HBA the 2nd zone dissapeared for some reason ? I don't know.
1 HBA connected to an SP port sees that port only, no way you can ever see another port. both HBA together can only see 2 ports, as you described it 1 port on SPA and another on SPB. I'd say on ESX1 you can see SPA0 and SPB0 and on the other host you can see SPA1 and SPB1.

Allen Ward · Answer

Right you are dynamox. I'm thinking that he may be remembering what things looked like on a host that was SAN connected not direct attached.

There is no way for a single HBA connected to a single SP port on a CLARiiON to see more than one target.

As for the question raised regarding communication over the CMI between SPs, this has nothing to do with what a host can see. A host can only see an SP that it has direct (or SAN zoned) connectivity to. The hosts described in the question should see a total of two paths each... one through each HBA.

kelleg · Answer

Sorry, what I meant to say was that if failover mode is set to 1 and you do not not failover software like Powerpath, you would see two instances of a single LUN - one down each path. Powerpath hides the non-owning SP path.

glen

Message was edited by:
kelleg

RRR · Answer

Is your question answered ? If so, please mark the question as such and reward points to the people who gave helpful and correct answers.

CLARiiON

ESX Multipath problem

Was this post helpful?