No, this is a common misconception. You don’t need any NSD servers. NSD servers are only needed if you have nodes without direct block access.
Remote cluster or not, disk access will be over local block device (without involving NSD servers in any way), or NSD server if local access isn’t available. NSD-servers are not «arbitrators» over access to a disk, they’re just stupid proxies of IO commands. -jf søn. 31. mai 2020 kl. 11:31 skrev Jonathan Buzzard < jonathan.buzz...@strath.ac.uk>: > On 29/05/2020 20:55, Stephen Ulmer wrote: > > I have a question about multi-cluster, but it is related to this thread > > (it would be solving the same problem). > > > > Let’s say we have two clusters A and B, both clusters are normally > > shared-everything with no NSD servers defined. > > Er, even in a shared-everything all nodes fibre channel attached you > still have to define NSD servers. That is a given NSD has a server (or > ideally a list of servers) that arbitrate the disk. Unless it has > changed since 3.x days. Never run a 4.x or later with all the disks SAN > attached on all the nodes. > > > We want cluster B to be > > able to use a file system in cluster A. If I zone the SAN such that > > cluster B can see all of cluster A’s disks, can I then define a > > multi-cluster relationship between them and mount a file system from A > on B? > > > > To state it another way, must B's I/O for the foreign file system pass > > though NSD servers in A, or can B’s nodes discover that they have > > FibreChannel paths to those disks and use them? > > > > My understanding is that remote cluster mounts have to pass through the > NSD servers. > > > JAB. > > -- > Jonathan A. Buzzard Tel: +44141-5483420 > HPC System Administrator, ARCHIE-WeSt. > University of Strathclyde, John Anderson Building, Glasgow. G4 0NG > _______________________________________________ > gpfsug-discuss mailing list > gpfsug-discuss at spectrumscale.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss >
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