[ipxe-devel] FCoE support in a multipath fabric

[Hannes Reinecke]

Hi all,

I'm trying to update iPXE to work in an FCoE VN2VN environment.
After quite some fiddling I've managed to get it to occasionally boot.
However, I've discovered an issue which continues to drag me down:
As it stands, iPXE assumes unique remote ports, identified by either the
port_id or the port_wwn.
In a multipath context this is no longer true; there one might have the
same remote port reachable from different local ports.
While this can be worked around by just enabling one device on the iPXE
side, you're still stuck if the same network device happens to present
you with _two_ (or several) FCoE initiator ports (as it might happen
once you discover several VLANs during FIP).

The main problem here is the 'fcp' URI specification; that just has

fcp://[remote-port]/[lun]

which is ambiguous once multipath is involved, making it anyone's guess
which remote port will be used for booting.

Would a patch to update the URI specification to

fcp://[local-port]/[remote-port]/[lun]

be acceptable?
Or is changing the URI a no-go?

(Incidentally, the same problem hits us with iSCSI; that's why we
have the 'last_used_netdev' hack ...)

THX.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare at suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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