From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Braam Date: Tue, 08 Jul 2008 11:43:39 -0600 Subject: [Lustre-devel] GSS cross-realm on MDT -> OST In-Reply-To: <4873A38C.4040507@sun.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org Yes, it will be very important that we can separate OST's/MDT's widely. But placing them in different realms, I'm not sure about. Can PSC explain what administrative model warrants that? Why can a remote OST not be part of the realm of the MDS that controls it? Peter On 7/8/08 11:27 AM, "Eric Mei" wrote: > Hi Ben, > > Benjamin Bennett wrote: >> Hi Eric, >> >> If you could give me your input on something I'd greatly appreciate >> it. Or, if I should just sent this to -devel let me know... > > Yes you can always send to -devel for open discussions. I'm CCing it. > >> For Lustre-WAN across TeraGrid we were hoping to distribute OSSs >> across several resource providers (sites), leveraging existing kerberos >> infrastructure, placing OSSs in each resource provider's local kerberos >> realm, and the MDS in the teragrid realm. Unfortunately, MDT -> OST >> connections will not allow the MDT and OST to be in different realms, >> since an OSS considers an MDS to be anyone holding a lustre_mds >> principal in their local realm. >> >> This also seems undesirable within a single-realm where multiple >> lustre clusters may exist, as an OSS in cluster A will trust an MDS for >> cluster B, and an OSS for cluster B will trust an MDS for cluster A. >> >> My first thought was to add functionality to tell the OSSs lsvcgssd >> what the trusted MDS principals should be (local or not). Do you have >> any thoughts on this? > > We just never thought the usage that OSS could locate in multiple > realms. I agree with you in this case, we can make OSS configurable to > only accept designated lustre_mds principals, local or remote. > > I'v questions just for curiosity: 1) is the benefit of cross site OSSs > about bandwidth? 2) in the future with CMD (clustered metadata, multiple > MDS nodes), would it be useful to distribute MDSs across multiple site > as well? > > Thanks