On 28 July 2010 09:45, Gianluca Cecchi <gianluca.cecchi@xxxxxxxxx> wrote:
> 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.
[snip]
> 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?
# lspci | grep QLogic
0d:00.0 Fibre Channel: QLogic Corp. ISP2432-based 4Gb Fibre Channel to
PCI Express HBA (rev 03)
0d:00.1 Fibre Channel: QLogic Corp. ISP2432-based 4Gb Fibre Channel to
PCI Express HBA (rev 03)
# ls -l /sys/class/fc_host/host?/device
lrwxrwxrwx 1 root root 0 Jul 28 11:54 /sys/class/fc_host/host1/device
-> ../../../devices/pci0000:00/0000:00:06.0/0000:0b:00.0/0000:0c:09.0/0000:0d:00.1/host1
lrwxrwxrwx 1 root root 0 Jul 28 11:55 /sys/class/fc_host/host0/device
-> ../../../devices/pci0000:00/0000:00:06.0/0000:0b:00.0/0000:0c:09.0/0000:0d:00.0/host0
(note the 0d:00.0 and 0d:00.1 PCI ID in the symlink targets)
And I believe:
# ls -l /sys/block/*/device
will show you the relationship between the block device and the FC
port you were looking for in d).
I would interpret your missing block devices as being each of your
target HBA seeing only one of the storage controllers, and not both -
but check the output of "ls -l /sys/block/{sdao,sdd}/device" to make
sure.
HTH.
>
> Thanks in advance,
> Gianluca
--
Jonathan Barber <jonathan.barber@xxxxxxxxx>
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