Hi Michael, I would suggest that replication factors which do not divide the keyspace are not going to cause problems, simply make sure you round any fractional numbers of keys in a consistent manner. A greater issue might be replication factors which do not divide the number of nodes, as this will lead to an uneven distribution of replicas over nodes. This is an issue I have run into myself - perhaps this is what you meant? I don't have any useful suggestions on this myself, yet.
The practicalities of replication in Chord quickly become somewhat fiendish. We've found that although using a second hash function to place replicas can increase performance, it is at the cost of considerable extra complexity. You can see my comparison of various replication schemes, including a form of symmetric replication in a paper I wrote for DASP2P-06. http://urchin.earth.li/~mleslie/mleslieStorage.pdf The 'Block' replication algorithm in my paper is an instance of symmetric replication, though it divides the nodes into equivalence classes in a slightly different way to that proposed in the paper by Ghosi et al. The most interesting thing we have found (I think) is that symmetric replication leads to a more reliable system for a given replication factor than DHash style replication - the authors of the original paper do not make this point. Matt PS: Sorry it took me so long to get round to replying, I hope this isn't irrelevant now. ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Hartmann Sent: 23 February 2006 17:20 To: p2p-hackers@zgp.org Subject: [p2p-hackers] Symmetric Replication for Chord Anyone actually tried implementing the replication scheme suggested by this paper: Symmetric Replication for Structured Peer-to-Peer Systems, A. Ghodsi, L-O Alima, S. Haridi, DBISP2P2005, 2005. http://dks.sics.se/pub/replication.pdf I am trying to implement it for Chord, it seems better than the successor-list approach, but I am wondering if it is possible to make it work for replication degrees that do not divide the size of the key space? Mike _______________________________________________ p2p-hackers mailing list p2p-hackers@zgp.org http://zgp.org/mailman/listinfo/p2p-hackers _______________________________________________ Here is a web page listing P2P Conferences: http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
