From: Lars Marowsky-Bree Date: Wed Jul 20 11:33:23 2005 Subject: [Ocfs2-devel] [RFC] nodemanager, ocfs2, dlm In-Reply-To: <20050720033546.GB9747@redhat.com> References: <20050718061553.GA9568@redhat.com> <20050719155214.GG13246@marowsky-bree.de> <20050720033546.GB9747@redhat.com> Message-ID: <20050720162636.GL5416@marowsky-bree.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: David Teigland Cc: linux-kernel@vger.kernel.org, linux-cluster@redhat.com, ocfs2-devel@oss.oracle.com On 2005-07-20T11:35:46, David Teigland 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-Br?e -- 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"