Full sparse support would be nice, but certainly not critical. I'd rather stay with what was considered least problematic. I'm re-examining any workarounds we use, to see if any of the issues have been resolved so any workarounds are no longer needed. As a general rule, without a reason to do otherwise, I like letting something run with defaults (where it would pick 4.2) rather than overriding something. So, with RDMA on 4.7.1+, no reason to stay on NFSv4.0 instead of NFSv4.1? On Thu, Aug 18, 2016 at 11:26 AM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > Hi James- > > >> On Aug 18, 2016, at 12:09 AM, james harvey <jamespharvey20@xxxxxxxxx> wrote: >> >> A year ago, on 7/30/2015, Chuck Lever said NFS/RDMA wasn't yet working >> with NFSv4.1 and NFSv4.2, as a known issue. >> >> I was able to use "vers=4.0" to get around the issue. >> >> I see v4.2 seems to mount properly, but before switching over to it, I >> wanted to see if it's considered stable, or still to be avoided. > > Can you tell why you'd like to use it? Which NFSv4.2 feature is interesting > to you? > > I don't test it regularly, simply because > > - The complete tests on each version take a long time to run > > - NFSv4.2 features are all optional, and the Linux NFSv4.2 implementation > adds only a couple that probably won't be affected by RDMA. READ_PLUS will > need some attention at some point, but I think Anna is still polishing the > upper layer implementation. > > - I don't have any specific tests for security labels, which add to the > size of the NFSv4 GETATTR receive buffer whether labels are actually > retrieved or not. So there is a little NFSv4.2 testing we get for free just > by using NFSv4.0. > > - There's yet a lot of non-version-specific work to do on RPC-over-RDMA. > > The main blocker before was support for bi-directional RPC, which all > minorversions of NFSv4 use after mv 1, and that should be working as well > as it does for NFSv4.1. > > NFSv4.2 itself should work, but I might choose to stay with NFSv4.1 for > now if it were up to me, unless you have need of one of the new features. > For example, there is no standard specification describing how READ_PLUS > is supposed to work on RPC-over-RDMA (that's in the works). > > > -- > Chuck Lever > > > -- 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
