iscsi lvm and /dev and bootup

[Bryn M. Reeves]

Harry Hoffman wrote:
> All of this works well and I can mount the filesystem just fine.
> 
> When I reboot it all goes to hell. I see iscsi logging into the lefthand
> box and it reports success.
> 
> and if I run vgdisplay I get:
>  vgdisplay external_iscsi
>   --- Volume group ---
>   VG Name               external_iscsi
>   System ID             
[snip]
> 
> however, there's no /dev/ entry for /dev/external_iscsi

Sounds like your VG has not been activated by your distribution's init
sripts. Run "vgchange -ay external_iscsi" and the VG should be activated
and made accessible, creating the entries in /dev. There's no need to
use the /dev/mapper/$vg-$lv entries - for LVM2 devices, the /dev/$vg/$lv
symlinks are guaranteed to be persistent.

What distro are you using here? Some perform a vgchange -ay from the
iscsi initialisation script (Fedora and RHEL both do this). If that's
not the case for your distribution then you might need to either add the
command to the script yourself, or make sure that if the distribution
provides an "lvm" initscript, that it's set to start later than the
iscsi script.

Assuming this is Fedora, it might be that it's taking a long time for 
the login to the storage to complete, and we're "missing" the VG when 
the vgchange in the iscsi script runs - I don't see a call to udevsettle 
in the script which would sync up with the new device discovery.

Regards,
Bryn.