Messages in this thread |  | | Date | Wed, 20 Jul 2005 18:26:36 +0200 | From | Lars Marowsky-Bree <> | Subject | Re: [Ocfs2-devel] [RFC] nodemanager, ocfs2, dlm |
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On 2005-07-20T11:35:46, David Teigland <teigland@redhat.com> wrote:
> > Also, eventually we obviously need to have state for the nodes - up/down > > et cetera. I think the node manager also ought to track this. > We don't have a need for that information yet; I'm hoping we won't ever > need it in the kernel, but we'll see.
Hm, I'm thinking a service might have a good reason to want to know the possible list of nodes as opposed to the currently active membership; though the DLM as the service in question right now does not appear to need such.
But, see below.
> There are at least two ways to handle this: > > 1. Pass cluster events and data into the kernel (this sounds like what > you're talking about above), notify the effected kernel components, each > kernel component takes the cluster data and does whatever it needs to with > it (internal adjustments, recovery, etc). > > 2. Each kernel component "foo-kernel" has an associated user space > component "foo-user". Cluster events (from userland clustering > infrastructure) are passed to foo-user -- not into the kernel. foo-user > determines what the specific consequences are for foo-kernel. foo-user > then manipulates foo-kernel accordingly, through user/kernel hooks (sysfs, > configfs, etc). These control hooks would largely be specific to foo. > > We're following option 2 with the dlm and gfs and have been for quite a > while, which means we don't need 1. I think ocfs2 is moving that way, > too. Someone could still try 1, of course, but it would be of no use or > interest to me. I'm not aware of any actual projects pushing forward with > something like 1, so the persistent reference to it is somewhat baffling.
Right. I thought that the node manager changes for generalizing it where pushing into sort-of direction 1. Thanks for clearing this up.
Sincerely, Lars Marowsky-Brée <lmb@suse.de>
-- High Availability & Clustering SUSE Labs, Research and Development SUSE LINUX Products GmbH - A Novell Business -- Charles Darwin "Ignorance more frequently begets confidence than does knowledge"
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