On 12/17/2010 06:55 PM, Rustad, Mark D wrote: > Hi all, > > I am looking into adding support for DCB into iSCSI. I think > it is best to do this in a way that will not require a strong > dependency on DCB for iSCSI. That is, installing open-iscsi > should not then require open-lldp to also be installed. I see > at least two ways to do this. > > The first is to have open-lldp supply a library that iscsid > can link with at run time (through dlopen/dlsym). In that way, > if the library is not there, iscsid can go on as usual. It > also allows lldpad more freedom to change over time. > > The second way is to put a little more code directly in > iscsid and have it interrogate lldpad for the proper priority > to set. If the lldpad socket isn't there, iscsid can go on as > usual. I am thinking that open-lldp can supply the source files > that would be placed directly into open-iscsi and updated as > needed. These source files might also be used by other network > applications that want to participate fully in a DCB environment. > > I had been leaning toward the first way until I started thinking > about iscsistart and initrds. Then it seemed that the run-time > linkage would create more trouble than it would be worth. > It started to seem like over-engineering. > I would prefer the second method. DCB configuration itself is quite involved and requires to negotiate the transfer parameter before the connection is setup. And as DCB is in fact quite a different beast from iSCSI we should keep it as a separate daemon. Which would also be in-line with the current fcoeadm setup.
> In either case, I was thinking about adding code right before > the connect() call in iscsi_io_tcp_connect to set the socket > options based on information from lldpad. Is anything more > than that needed (besides doing something similar in iscsistart)? > VLAN creation. >From what I've seen iSCSI support in DCB would work similar to FCoE, ie the iSCSI traffic will be sent via a separate VLAN. Which we would need to create, eventually. So basically we would need something similar to 'fipvlan' or integrate this functionality into open-iscsi. > The socket protocol to lldpad is already versioned, so that > should prevent any terribly rude surprises in the future should > mismatched components be used together. > > Does this sound reasonable to you? Would you rather see it done > in a different way? Would you prefer for iscsid to simply send > a file descriptor to the lldpad socket and have lldpad set the > socket options itself? > Ugh. No. As mentioned, I fear we would need to setup a VLAN interface here, in which case we would be running off a totally different socket anyway. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage h...@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg) -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-is...@googlegroups.com. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.
