On Mon, 2010-05-03 at 17:14 -0400, maillists0@xxxxxxxxx wrote: > On Mon, May 3, 2010 at 3:25 PM, Trond Myklebust > <trond.myklebust@xxxxxxxxxx> wrote: > > On Mon, 2010-05-03 at 14:56 -0400, J. Bruce Fields wrote: > >> On Mon, May 03, 2010 at 12:53:15PM -0400, maillists0@xxxxxxxxx wrote: > >> > With NFS4's support for referrals and Kerberos, it seems like the > >> > original reasons to prevent re-exporting of an NFS share might no > >> > longer exist. With fs-proxy making its way into the mainline kernel > >> > and things like cachefilesd, there are also very good reasons to allow > >> > it. A proxy server with a persistent cache could give the ability to > >> > robustly use shares across a WAN or do failover pairs with no need for > >> > more complex replication. Speaking as an end-user, this would be very > >> > desirable. > >> > > >> > I see that others have implemented proxies with user-space NFS, which > >> > seems reasonable but not optimal. What is the obstacle to allowing > >> > re-exports with the standard nfs implentation? Is it possible at the > >> > moment to patch a kernel to make this work? Anyone have experience > >> > with it? Any input is appreciated. > >> > >> It's probably possible, but some kernel hacking would be required. > >> > > Have a look at this old thing from 2006: > http://www.usenix.org/event/fast07/tech/full_papers/gulati/gulati_html/nache.html > . They claim to have implemented a proxy with only the tools I > mentioned above, along with their own modified version of nfs to allow > multi-hops. > > I have a workload of lots of reads/almost no writes, and their > approach makes sense. It would be a great feature. Is something > missing from that paper that makes it unrealistic? Possibly not for your workload, but none of the issues Bruce and I raised appear to be addressed in that paper. Furthermore, we do know several of the authors, and none of them have ever approached us with a proposal to merge their implementation. I therefore assume that it was written more as a proof of concept in support of the paper, rather than something IBM is actually planning to market. 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
