On Mon, 19 Dec 2016, David Teigland wrote: > On Sun, Dec 18, 2016 at 08:46:25PM +0100, Jean-Marc Saffroy wrote: > > Hi (again), > > > > Another question I have regarding DLM and Corosync (because Corosync is > > required to use DLM): should I expect compatibility across versions? > > > > I did a quick test between distributions running different kernels (CentOS > > 6, Centos7 and Ubuntu 14) but rather close versions of Corosync, and that > > test worked, but I am not sure if that was just luck. ;) > > I can only speak for the dlm part of that. Between different > distributions, I'd call it luck :) Ah, so that could be a serious problem for me. I hoped to be able to use dlm across distributions without having to qualify each possible combination... > Within the context of one distribution things shouldn't break if the > distribution is doing it's job. Does that mean that, for example, I could expect dlm instances in RHEL6 and RHEL7 kernels to work together? > Upstream, with no distribution context, I'm certainly aware of when > compatibility breaks between dlm_controld and corosync and between > different dlm_controld versions on nodes. I try to avoid it, but there > are unpredictable reasons that it can break. How could instances of dlm_controld interact badly? I thought they were just glue between dlm and corosync, and never directly talk on the network. Do they have network-visible side effects on dlm/corosync? In the end, I need to work across distributions and their kernels, but I could build from source a specific version of corosync and (the userland part of) dlm. I expect that the kernel interface to dlm is stable (right?), so the biggest risk would be incompatibilities in the dlm protocol on the network. Is this protocol stable? With git I see that DLM_HEADER_MAJOR/MINOR macros changed very rarely in recent years but I can't tell if this is a good indicator. Cheers, JM -- saffroy@xxxxxxxxx -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
