Can we let the choice to the client if the session trunking is manual or automatic? Manual : with the load-balancing algorithm of his choice Automatic : with a smarter algorithm just as M. Fields says, like an adaptative load-balancing algo. for example. Martin 2016-02-18 15:14 GMT+01:00 J. Bruce Fields <bfields@xxxxxxxxxxxx>: > On Wed, Feb 17, 2016 at 06:55:43PM -0500, Trond Myklebust wrote: >> On Wed, Feb 17, 2016 at 5:52 PM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: >> > >> >> On Feb 17, 2016, at 5:35 PM, Adamson, Andy <William.Adamson@xxxxxxxxxx> wrote: >> >> The fs_locations would need to be requested by the client. I guess we reqest them at every mountâ€Ķ. >> > >> > Yep, and fetch them again every so often. There's no real >> > cache coherency protocol for this information. (That's >> > where a pNFS layout might be more valuable). >> >> If your goal is to do session trunking, you only really need to check >> the fs_locations attribute on the root file system. (so >> GETROOTFH+GETATTR(fs_locations)). That's the natural place for a >> server to advertise its full set of IP addresses, and the session >> trunking protocol itself will allow you to winnow out any that might >> belong to a replica server. > > I worry that round-robin could behave really badly if the client's path > to the two IP addresses have different performance characteristics. But > a server should probably still be allowed to advertise those as replicas > (e.g. maybe a slower interface is usable as a fallback?). > > So maybe we should be careful about making this automatic. Unless the > load-balancing is a little smarter than pure round robin. Or unless we > can get some more fine-grained information (maybe someone could use > fs_location_info's preference information for this?). > > --b. > >> >> You might want to refresh that info whenever the connection goes away >> on one or more addresses without a reboot so you can detect when NICs >> are going away. >> >> Otherwise, polling every couple of hours or so for new NICs shouldn't >> be too burdensome... >> >> Cheers, >> Trond -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
