From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Nowoczynski Date: Wed, 20 Oct 2010 13:25:15 -0400 Subject: [Lustre-devel] Queries regarding LDLM_ENQUEUE In-Reply-To: <4CBF2483.7030805@gmail.com> References: <4CBEA415.80307@gmail.com> <9C26CBA7-8DBD-4875-8E14-FB663B749096@oracle.com> <4CBEA8A9.9080802@gmail.com> <00d001cb705a$fd64cb80$f82e6280$@com> <4CBF01DA.3090505@psc.edu> <4CBF094A.9020302@gmail.com> <4CBF1C42.1090109@psc.edu> <4CBF1D82.60508@gmail.com> <4CBF22DE.9080204@psc.edu> <4CBF2483.7030805@gmail.com> Message-ID: <4CBF25FB.5030708@psc.edu> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org have a look at this, it explains the type of problem networks have in dealing with these communication patterns. http://www.pdl.cmu.edu/Incast/ and yes, a proxy is a workable solution, and probably the most well rounded. The disadvantages is that it would presumably require more engineering to deploy. p bzzz.tomas at gmail.com wrote: > On 10/20/10 9:11 PM, Paul Nowoczynski wrote: > >> I could be wrong but my guess is that the network congestion caused by >> this communication pattern is a more serious problem. The mds should be >> able to easily service lookup rpc's since only the first few necessitate >> a read I/O from the disk. >> > > but then the network should be able to deal with storm of > * <# clients> to read/write data? > > or it's a specific switch being the bottleneck to specific node? > > because if it isn't network, but MDS being a real bottleneck, > then proxy might be a solution like Eric said above. not sure > is this important in your case, but this would allow to use > existing apps. > > of course, distribution tree for a handle may scale better. > > thanks, z > _______________________________________________ > Lustre-devel mailing list > Lustre-devel at lists.lustre.org > http://lists.lustre.org/mailman/listinfo/lustre-devel >