[dm-devel] NIC and HBA based multipathing

[Scott Moseman]

On Nov 15, 2007 1:16 PM, Mike Anderson <andmike at linux.vnet.ibm.com> wrote:
>
> > >> I can use 'mknod sdc b 8 32' to generate a new /dev/sdc, which I can
> > >> fdisk and the data looks good, but once I reboot the /dev/sdc device
> > >> is once again removed (or not re-created, whichever the case may be).
>
> I would agree that we should look to see what udev is doing when it
> receives the events.
>
> Since I believe this is failing on a RHEL4 sytem we cannot use
> udevmonitor. If you unload the iSCSI module, edit /etc/udev/udev.conf to
> set udev_log="yes", and then load the module again you should get some info
> in /var/log/message on what udev is doing.
>

Hey Mike,

Here's the guts of what happened...

# cat /var/log/messages | grep udev
Nov 13 15:39:01 ems1 udevsend[1185]: starting udevd daemon
Nov 13 15:39:02 ems1 start_udev: Starting udev:  succeeded
Nov 13 15:39:06 ems1 udevsend[1691]: starting udevd daemon
Nov 15 20:13:58 ems1 udev[30499]: creating device node '/dev/iscsictl'
Nov 15 20:13:58 ems1 udev[30509]: creating device node '/dev/iscsictl'
Nov 15 20:14:03 ems1 udev[30551]: configured rule in
'/etc/udev/rules.d/20-local.rules' at line 2 applied, 'sdc' is ignored
Nov 15 20:14:03 ems1 udev[30552]: configured rule in
'/etc/udev/rules.d/51-by-id.rules' at line 4 applied, added symlink
'disk/by-id/scsi-%c-part%n'
Nov 15 20:14:03 ems1 udev[30552]: creating device node '/dev/sdc1'

# cat /etc/udev/rules.d/20-local.rules
BUS="scsi", SYSFS{vendor}="EQLOGIC", SYSFS{model}="100E-00",
PROGRAM="/sbin/scsi_id -g -u -s /block/%k",
RESULT="30690a018f015191a6472441d1500f057", NAME=""

Maybe I shot myself in the foot.  While I don't necessarily recall
very putting that entry in there, I'm not going to exclude myself as
the cause of the problem (seeing how many steps I jumped through when
playing with all of this HBA, NIC and MPIO stuff).

Should I comment out that line, reboot (or restart iscsi) and see what happens?

Thanks!
Scott