On 12/15/2011 11:47 PM, Shumate, Scott wrote:
I have an issue with zfcp luns. I 2 luns 1 100GB lun and 1 1GB lun.
The 100GB lun has 4 paths /dev/sda, /dev/sdb, /dev/sdd, and /dev/sde.
The 1GB lun has one path /dev/sdc. I want paths /dev/sda thru /dev/sdd
for the 100GB lun and /dev/sde for the 1GB lun. Is there anything I can
do to make this happen? I've manually removed the scsi disk and
rebooted, but it still has the same issue. What am I doing wrong?
No issue here. /dev/sdX are kernel device names allocated by no
particular rule a user can rely on. Therefore, udev provides persistent
device names implemented by means of symbolic links under /dev. For
storage, those can be found under /dev/disk/by-.../...
For those cases where I really need to refer to an individual path of a
zfcp attached SCSI disk, I usually rely on
/dev/disk/by-path/ccw-<devbusid>-zfcp-<wwpn>:<lun>.
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/persistent_naming.html
and also the Section "SCSI device nodes" in the zfcp chapter in the
"Device Drivers, Features, and Commands" book on
http://www.ibm.com/developerworks/linux/linux390/documentation_red_hat.html#rhel5
Just curious: Having configured multiple paths I presume you use
device-mapper multipathing on top which doesn't care about the device
names of individual paths.
What do you need device names of underlying physical paths for?
[root@wil-zstsintgdbprdbu01 ~]# cat /etc/zfcp.conf
0.0.dc00 0x50060e800571f006 0x0020000000000000
0.0.dd00 0x50060e800571f016 0x0020000000000000
0.0.de00 0x50060e800571f007 0x0020000000000000
0.0.df00 0x50060e800571f017 0x0020000000000000
This only contains persistent configuration for four paths to your
presumable 1GB LUN. However, where does the config for the one path to
the 100GB LUN come from?
[root@wil-zstsintgdbprdbu01 ~]# lszfcp -D
0.0.dc00/0x50060e800571f006/0x0020000000000000 0:0:0:1
0.0.dc00/0x50060e800571f006/0x0026000000000000 0:0:0:2
0.0.dd00/0x50060e800571f016/0x0020000000000000 1:0:0:1
0.0.de00/0x50060e800571f007/0x0020000000000000 2:0:0:1
0.0.df00/0x50060e800571f017/0x0020000000000000 3:0:0:1
[root@wil-zstsintgdbprdbu01 ~]# lsscsi
[0:0:0:1] disk HITACHI OPEN-V 6008 /dev/sda
[0:0:0:2] disk HITACHI OPEN-V 6008 /dev/sdc
[1:0:0:1] disk HITACHI OPEN-V 6008 /dev/sdd
[2:0:0:1] disk HITACHI OPEN-V 6008 /dev/sde
[3:0:0:1] disk HITACHI OPEN-V 6008 /dev/sdb
Looks perfectly good to me.
Steffen
Linux on System z Development
IBM Deutschland Research & Development GmbH
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