Primary and Alternate PV links on the same FC adapter

[Joe Choo]

I recently took over management of a HP-UX 11.11 server that had connections to SAN storage - EMC CLARIION and noticed something very strange about it.

I have 3 FC adpaters, but only 1 is used and connected.

# ioscan -nufCfc
Class I H/W Path Driver S/W State H/W Type Description
=================================================================
fc 0 0/8/0/0 td CLAIMED INTERFACE HP Tachyon XL2 Fibre Channel Mass Storage Adapter
/dev/td0
fc 1 0/9/0/0 td CLAIMED INTERFACE HP Tachyon XL2 Fibre Channel Mass Storage Adapter
/dev/td1
fc 2 0/12/0/0 td CLAIMED INTERFACE HP Tachyon XL2 Fibre Channel Mass Storage Adapter
/dev/td2

# ioscan -nufCfcp
Class I H/W Path Driver S/W State H/W Type Description
====================================================================
fcp 7 0/9/0/0.29 fcp CLAIMED INTERFACE FCP Domain
fcp 9 0/9/0/0.57 fcp CLAIMED INTERFACE FCP Domain -Note : Domain is like a zone
fcp 12 0/9/0/0.75 fcp CLAIMED INTERFACE FCP Domain

It seems also the primary and alternate PV links are essentially on the same FC adapter.

I know for sure there isn't any redundancy from the server end, but at the FC switches end (there should be 2 for redundancy), does this mean that they have exported to the same WWN ID of the FC adapter?

I'm pretty sure my FC adapter is a single port adapter.

PV Name /dev/dsk/c29t0d1
PV Name /dev/dsk/c28t0d1 Alternate Link
PV Status available
Total PE 2079
Free PE 1079
Autoswitch On


fcp 12 0/9/0/0.75 fcp CLAIMED INTERFACE FCP Domain
ext_bus 28 0/9/0/0.75.0.228.0 fcparray CLAIMED INTERFACE FCP Array Interface
disk 71 0/9/0/0.75.0.228.0.0.0 sdisk CLAIMED DEVICE DGC CX600WDR3
/dev/dsk/c28t0d0 /dev/rdsk/c28t0d0
disk 82 0/9/0/0.75.0.228.0.0.1 sdisk CLAIMED DEVICE DGC CX600WDR3
/dev/dsk/c28t0d1 /dev/rdsk/c28t0d1
...
ext_bus 29 0/9/0/0.75.0.232.0 fcparray CLAIMED INTERFACE FCP Array Interface
disk 81 0/9/0/0.75.0.232.0.0.0 sdisk CLAIMED DEVICE DGC CX600WDR3
/dev/dsk/c29t0d0 /dev/rdsk/c29t0d0
disk 83 0/9/0/0.75.0.232.0.0.1 sdisk CLAIMED DEVICE DGC CX600WDR3
/dev/dsk/c29t0d1 /dev/rdsk/c29t0d1

[Steven E. Protter]

Shalom,

There is no redundancy except perhaps in the fabric network you are connected to. This is due to unusual network design.

Two switches, two pathes, confused HP-UX system.

Its more reliable than a single switch system because a switch can go and you don't go offline.

SEP

[Yang Qin_1]

You have EMC powerpath installed on that server. The Alternate Link is not from a "ghost" FC on the server but from other Fabric switch port to the second SP in Clariion box.

Check if you have /opt/EMCpower or run command "/sbin/powermt display dev=all" if you have powermt command and you get the output from that command, it means you have it EMC poerpath installed. PowerPath discover all pathes in whole SAN and make all of them visible on your server. It also make path failover and load balance automatically.

Yang

[Joe Choo]

Thanks Guys.

No I didn't find the powermt command or the EMCPower directory path in the server. It's not my company's policy to install it anyway.

So with that being said, can I safely say that this server really has only 1 physical path to the switch ?

Joe

[Yang Qin_1]

Yes, the device files /dev/dsk/c28/t0d# and /dev/dsk/c29t0d# listed above are configured with the same FC -- 0/9/0/0

If you run xstm (in X-window) you can easily identify it.


Yang

[Joe Choo]

Thanks Again.

[Joe Choo]

Thanks all.

I'll need to work with storage team to fix this issue.

Joe