----- On Jun 7, 2016, at 12:28 PM, Sven Moeller smoel...@nichthelfer.de wrote:
> Hi, > > > Am Dienstag, 07. Juni 2016 11:42 CEST, "Lentes, Bernd" > <bernd.len...@helmholtz-muenchen.de> schrieb: > >> >> >> ----- On Jun 6, 2016, at 8:17 PM, Digimer li...@alteeve.ca wrote: >> >> >> Ok. Does DLM takes care that a LV just can be used on one host ? >> cLVM just takes care that the naming is the same on all nodes, right ? > > AFAIK DLM takes care about the LVM Locking cluster wide. What does that mean concretely, "LVM Locking cluster wide" ? I read it always, but no explaination. Does that mean that a LV just can be accesses from one node ? That DLM "locks" (in the sense of "blocking the other node") the access ? Or does the LV has to be a cluster ressource to prevent concurrent access ? >> >> >> Later on it's possible that some vm's run on host 1 and some on host 2. >> >> Does >> >> clvm needs to be a ressource managed by the cluster manager ? >> > >> > Yes, you can live-migrate as well. I do this all the time, except I use >> > DRBD instead of a SAN and RHEL instead of SUSE, but those are trivial >> > differences in this case. >> > >> >> If i use a fs inside the lv, a "normal" fs like ext3 is sufficient, i >> >> think. But >> >> it has to be a cluster ressource, right ? >> > >> > You can format a clustered LV with a cluster unaware filesystem just >> > fine. However, the FS is not made magically cluster aware... If you >> > mount it on two nodes, you will almost certainly corrupt the FS quickly. >> > If you want to mount an LV on two+ nodes at once, you need a >> > cluster-aware file system, life GFS2. >> >> No. Pacemaker takes care that the FS is just mounted on one node. >> So it should not be a problem ? > > If you want to be sure to mount an LV on just one Node, you have to activate > the > VG exclusively on one node. You have to configure the ressource for the VG > accordingly. Otherwise it's possible to activate and mount an LV on several > nodes at the same time, even with a non Cluster FS, e.g. ext4, which would end > up in corrupted FS, most likely. (as mentioned above allready). But maybe i want to have some vm's running on host A and others on host B. Remember: one vm per LV. So i need access to the VG concurrently from both nodes, right ? But if the FS from the LV is a cluster ressource, pacemaker takes care the the FS is mounted just from one node. I can rely it on it, right ? That's what i read often. But what if i don't have a FS ? It's possible to have vm's in plain partitions, which should be a performance advantage. Bernd Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Aufsichtsratsvorsitzende: MinDir'in Baerbel Brumme-Bothe Geschaeftsfuehrer: Prof. Dr. Guenther Wess, Dr. Alfons Enhsen, Renate Schlusen (komm.) Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671 _______________________________________________ Users mailing list: Users@clusterlabs.org http://clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org