[Linux-cluster] CLVMD without GFS

[Christine Caulfield]

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 <ccaulfie at redhat.com
> <mailto:ccaulfie at redhat.com>>:
>
>     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
>
>
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