From owner-nwchem-users@emsl.pnl.gov Mon Jul 26 01:13:38 2004 Received: from odyssey.emsl.pnl.gov (localhost [127.0.0.1]) by odyssey.emsl.pnl.gov (8.12.10/8.12.10) with ESMTP id i6Q8DcHQ025731 for ; Mon, 26 Jul 2004 01:13:38 -0700 (PDT) Received: (from majordom@localhost) by odyssey.emsl.pnl.gov (8.12.10/8.12.10/Submit) id i6Q8DcX5025730 for nwchem-users-outgoing; Mon, 26 Jul 2004 01:13:38 -0700 (PDT) Date: Mon, 26 Jul 2004 10:11:30 +0200 (CEST) From: Giacomo Mulas Subject: Re: fast ethernet In-reply-to: To: nwchem_users Reply-to: Giacomo Mulas Message-id: MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII X-OAC-capitanata-MailScanner: Found to be clean References: Sender: owner-nwchem-users@emsl.pnl.gov Precedence: bulk On Sun, 25 Jul 2004, Richard Casey wrote: > One of the FAQ's on the NWChem site states that Myrinet or Giganet > should be used for large Linux clusters. Suppose however that we have a > small Linux cluster with Fast Ethernet (I.e. 6 CPU's on 3 nodes, with 2 > CPU's per node). To run NWChem in parallel on such a cluster, do we > have to recompile the source code or can we use the binaries as > distributed in v.4.5? The 4.5 binaries can be used in parallel, using the included "parallel" command, but as far as I can tell this is meant to be used on SMP machines, not on clusters. I am almost sure that you need to recompile from sources if you want MPI support, which you need to run parallel jobs on a cluster of distinct machines. However I am an (ab)user, not a NWChem developer, therefore you'd better wait for some of them to confirm this. I would like to ask an additional question, though: if one wants to run NWChem in MPI mode on a cluster of Linux PCs, is a coherent filesystem required? NFS does not guarantee coherence across nodes mounting the same filesystem, for example, and any coherent cluster filesystem (e.g. PVFS, GFS, Lustre...) requires far more work to set up, hence I would like to know whether it is necessary/recommended/unneeded/whatever. Thanks Giacomo -- _________________________________________________________________ Giacomo Mulas _________________________________________________________________ OSSERVATORIO ASTRONOMICO DI CAGLIARI Str. 54, Loc. Poggio dei Pini * 09012 Capoterra (CA) Tel. (OAC): +39 070 71180 248 Fax : +39 070 71180 222 Tel. (UNICA): +39 070 675 4916 _________________________________________________________________ "When the storms are raging around you, stay right where you are" (Freddy Mercury) _________________________________________________________________