It looks like you only have one real FCP path to that LUN, correct?
Devices 601 and 603 are probably on the same chpid, and you are accessing
lun 0001 through the same WWPN. ( BTW - is that LUN number right? If it's
on a Shark device, every LUN I've ever seen has been in the 5000-5FFF
range. But if you've tried accessing it with a single path and it works,
then never mind... )
Also - I think you may run into a problem accessing the same LUN more than
once through a single WWPN. You may have to have more than one WWPN to do
multipathing - otherwise the zfcp driver will throw that error message
about accessing the same LUN more than once. Basically - this means you
probably need to have more than one adapter in your Shark ( Or other back
end dasd ) defined as open systems SCSI FCP. Also - at the moment, Linux
on Z needs to have a FCP switch in between the Z and the back end storage
system. Direct connect is not supported with FCP - it needs the switch's
nameserver to work.
I'm not sure what benifit you'd get by having multiple paths to a single
LUN - I can't say for sure if you get multiple IO's in flight at one time
to the one device ( like with PAV ) or not. The real benifit of SCSI
multipathing from my understanding is from having multiple LUNs accessed
by multiple paths so you can drive more than one device simultaneously.
Well - that and the no single point of failure.
Anyway - heres what I would suggest to do Multipathing the way I
understand it:
Device 701 is on a different FCP chpid than 601, and I've changed the WWPN
that 701 talks to to be different ( ...c7...) than the one on adapter 601
( ...c5...)
I've also changed the LUN number to be in the 5000-5FFF range ( to match
what I know about zLinux's SCSI needs & related Sharkness ) and and added
another lun to show how you'd do more than one.
rmmod zfcp
modprobe qdio
modprobe scsi_mod
insmod zfcp map="\
0x601 0x01:0x500060e802c5d603 0x00:0x5001000000000000;\
0x601 0x01:0x500060e802c5d603 0x01:0x5002000000000000;\
0x701 0x01:0x500060e802c7d603 0x00:0x5001000000000000;\
0x701 0x01:0x500060e802c7d603 0x01:0x5002000000000000"
modprobe sd_mod
modprobe st
This should get you up with multiple paths to the devices. You'll end up
with something like /dev/sda pointing to the first path to 5001, /dev/sdb
pointing to the first path to 5002, /dev/sdc pointing to the second path
to 5001, and /dev/sdd pointing to the second path to 5002. Look at the
startup messages carefully, or at the dmesg output to verify this.
Then you'll probably want to use LVM ( on SuSE ) or mdadm ( on RedHat ) to
setup consolidated devices to access your disks. With LVM just create your
logical volume on the first set of paths to the devices as you normally
would, then use the pvpath command to enable the extra paths. With mdadm -
sorry - I can't help there. I've never used that tool. If you need
directions on how to do multipathing on RedHat contact me off list and
I'll forward you to the right people.
Jay Brenneman
Linux Test and Integration Center
T/L: 295 - 7745
Extern: 845 - 435 - 7745
[EMAIL PROTECTED]
Herve Bonvin <[EMAIL PROTECTED]>
Sent by: Linux on 390 Port <[EMAIL PROTECTED]>
03/27/2004 02:00 AM
Please respond to Linux on 390 Port
To: [EMAIL PROTECTED]
cc:
Subject: Multipathing with SCSI on FCP
Hi,
Has anybody tried multipathing with SCSI on FCP ?
I tried to defined 2 path to the same WWPN/LUN with 2 differents devices
numbers on the same linux and I get the following error :
Mar 27 07:59:04 sbe12127 kernel: Loaded 10178 symbols from
/boot/System.map-2.4.21-83-default.
Mar 27 07:59:04 sbe12127 kernel: Symbols match kernel version 2.4.21.
Mar 27 07:59:04 sbe12127 kernel: Loaded 516 symbols from 18 modules.
Mar 27 07:59:04 sbe12127 kernel: scsi : 0 hosts left.
Mar 27 07:59:04 sbe12127 kernel: zfcp: zfcp_module_init: driver version
0x3009d
Mar 27 07:59:05 sbe12127 kernel: zfcp: FSF: zfcp_fsf_open_unit_handler:
FSF_LUN_IN_USE
Mar 27 07:59:05 sbe12127 kernel: zfcp: FSF: zfcp_fsf_open_unit_handler:
error: FCP_LUN 0x0001000000000000 at the remote port with WWPN
0x500060e802c5d603 connected to the adapter with devno 0x0601 is already
owned by another operating system instance (LPAR or VM guest)
Mar 27 07:59:05 sbe12127 kernel: zfcp: FSF: zfcp_fsf_open_unit_handler:
Additional sense data is presented:
Mar 27 07:59:05 sbe12127 kernel: 00bb0f03 00000000 00000000 00000000
Mar 27 07:59:05 sbe12127 kernel: zfcp: ERP: zfcp_erp_unit_failed: Unit
recovery failed on the unit with FCP_LUN 0x0001000000000000 connected to
the port with WWPN 0x500060e802c5d603 at the adapter with devno 0x0601.
Mar 27 07:59:05 sbe12127 kernel: scsi0 : zfcp
Mar 27 07:59:05 sbe12127 kernel: scsi1 : zfcp
here the scripts :
rmmod zfcp
modprobe qdio
modprobe scsi_mod
insmod zfcp map="\
0x601 0x01:0x500060e802c5d603 0x00:0x0001000000000000;\
0x603 0x02:0x500060e802c5d603 0x01:0x0001000000000000"
modprobe sd_mod
modprobe st
Thanks in advance,
Herve Bonvin
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