[dm-devel] [OT] How to associate pci id with wwpn for an hba

[Gianluca Cecchi]

Hello,
yesterday I had a problem where a server with 2 Qlogic HBA detected only 2
of the 4 paths it should see.
Each HBA is connected to a different fc switch.
Each FC switch is connected to the 2 controllers of an IBM DS6800 storage
array.
So that in general each disk is seen by 4 paths.
System is rh el 5.5 x86_64
Something like this for each mpath device normally:

mpath1 (3600507630efe0b0c0000000000000601) dm-8 IBM,1750500
[size=15G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=0][active]
 \_ 1:0:3:2  sdao 66:128 [active][undef]
 \_ 2:0:3:2  sdaq 66:160 [active][undef]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:2:2  sdd  8:48   [active][undef]
 \_ 2:0:2:2  sdp  8:240  [active][undef]

Yesterday one server was able to see only 2 paths for each mpath device.
I had something like this:
mpath1 (3600507630efe0b0c0000000000000601) dm-8 IBM,1750500
[size=15G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=0][active]
 \_ 1:0:3:2  sdao 66:128 [active][undef]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:2:2  sdd  8:48   [active][undef]

I had some problems to identify PCI ID <--> WWPN <--> disk devices
associations so that I could give the correct wwpn involved in the problem
to the SAN guys for analysis and resolution.

I took these steps. Could anyone confirm they are ok or provide other
analysys information?

a) From above output of "multipath -l", and also from output of "lsscsi"
command
..
[1:0:2:2]    disk    IBM      1750500          .508  /dev/sdd
[1:0:2:3]    disk    IBM      1750500          .508  /dev/sde
..
[1:0:3:0]    disk    IBM      1750500          .508  /dev/sdal
[1:0:3:1]    disk    IBM      1750500          .508  /dev/sdan
[1:0:3:2]    disk    IBM      1750500          .508  /dev/sdao

with only lines of kind "1:0:x:x" I concluded that I had one adapter
correctly seeing its 2 paths and the other one seeing nothing.

b) In /var/log/messages I had this, only for one adapter
Jul 27 17:54:58 orastud1 kernel: qla2xxx 0000:06:00.0: SNS scan failed --
assuming zero-entry result...

that confirmed somehow a) conclusion

Now I had to give wwpn of hba with pci id 0000:06:00.0
I found that this was not so obvious (at least for me)

c) to see my two wwpn:
# for i in 1 2 ; do echo "host$i $(cat
/sys/class/fc_host/host$i/port_name)"; done
host1 0x21000024ff288e04
host2 0x21000024ff288e05

ok: how to directly connect hostx with pci 0000:06:00.0 ?
lspci  gives:
06:00.0 Fibre Channel: QLogic Corp. ISP2532-based 8Gb Fibre Channel to PCI
Express HBA (rev 02)
06:00.1 Fibre Channel: QLogic Corp. ISP2532-based 8Gb Fibre Channel to PCI
Express HBA (rev 02)

but no "-vv" switch gives the wwpn for them
Can I surely say that host1 <--> 06:00.0 and host2 <--> 06:00.1 ?
What if the first number in general is not the same (for example first hba
05:00.0 and second 06:00.0)?

d) Basically I went through something like:
# ls -d /sys/class/fc_transport/target*/device/*/block* | grep sdao
/sys/class/fc_transport/target1:0:3/device/1:0:3:2/block:sdao
# ls -d /sys/class/fc_transport/target*/device/*/block* | grep sdd
/sys/class/fc_transport/target1:0:2/device/1:0:2:2/block:sdd

Can I say that host1 <--> target1 ?
And so that in my case the adapter not seeing the LUNs was host2 ----> wpn
0x21000024ff288e05 ?

Could I directly say from point a) that the hostx involved is host2 as
"multipath -l" only shows 1:x:y:z devices?
And so that problematic wpn was 0x21000024ff288e05?
Anyway, how to associate hostx with pci id?

Thanks in advance,
Gianluca
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