Well, Pointless, I'm not sure as you take advantage of having all the other nodes in the cluster updated if a LVM metadata is modified by the node holding the VG.
Second point, HA-LVM aka hosttags has, IMHO, a security problem as anyone could modify the hosttag on a VG without any problem (no locking mechanisms as CLVM). I have nothing against Clustered FS, but in my specific case, I have to host serveral Sybase Dataservers on some clusters, and the only acceptable option for my DBA's is to use raw devices. I never meant to combine HA-LVM and CLVM, I consider them mutualy exclusive. Regards 2009/7/21, Christine Caulfield <[email protected]>: > > It seems a little pointless to integrate clvmd with a failover system. > They're almost totally different ways of running a cluster. clvmd assumes a > symmetrical cluster (as you've found out) and is designed so that the LVs > are available on all nodes for a cluster filesystem. Trying to make that > sort of system work for a failover installation is always going to be > awkward, it's not what it was designed for. > > That, in part I think, is why HA-LVM checks for a clustered VGs and > declines to manage them. A resource should be controlled by one manager, not > two, it's just asking for confusion. > > Basically you either use clvmd or HA-LVM; not both together. > > If you really want to write a resource manager to use clvmd then feel free, > I don't have any references but others might. It's not an area I have ever > had to go into. > > Good luck ;-) > > Chrissie > > > > On 07/21/2009 03:40 PM, brem belguebli wrote: > >> Hi, >> That's what I 'm trying to do. >> If you mean lvm.sh, well, I've been playing with it, but it does some >> "sanity" checks that are wierd >> >> 1. It expects HA LVM to be setup (why such check if we want to use >> CLVM). >> 2. it exits if it finds a CLVM VG (kind of funny !) >> 3. it exits if the lvm.conf is newer than /boot/*.img (about this >> one, we tend to prevent the cluster from automatically starting ...) >> >> I was looking to find some doc on how to write my own resources, ie CLVM >> resource that checks if the vg is clustered, if so by which node is it >> exclusively held, and if the node is down to activate exclusively the VG. >> If you have some good links to provide me, that'll be great. >> Thanks >> >> >> 2009/7/21, Christine Caulfield <[email protected] >> <mailto:[email protected]>>: >> >> On 07/21/2009 01:11 PM, brem belguebli wrote: >> >> Hi, >> When creating the VG by default clustered, you implicitely >> assume that >> it will be used with a clustered FS on top of it (gfs, ocfs, >> etc...) >> that will handle the active/active mode. >> As I do not intend to use GFS in this particular case, but ext3 >> and raw >> devices, I need to make sure the vg is exclusively activated on one >> node, preventing the other nodes to access it unless it is the >> failover >> procedure (node holding the VG crashed) and then re activate it >> exclusively on the failover node. >> Thanks >> >> >> >> In that case you probably ought to be using rgmanager to do the >> failover for you. It has a script for doing exactly this :-) >> >> Chrissie >> >> >> -- >> Linux-cluster mailing list >> [email protected] <mailto:[email protected]> >> https://www.redhat.com/mailman/listinfo/linux-cluster >> >> >> >> ------------------------------------------------------------------------ >> >> -- >> Linux-cluster mailing list >> [email protected] >> https://www.redhat.com/mailman/listinfo/linux-cluster >> > > -- > Linux-cluster mailing list > [email protected] > https://www.redhat.com/mailman/listinfo/linux-cluster >
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