Am Montag, 9. März 2009 18:01:08 schrieb David Lang: > On Fri, 6 Mar 2009, Michael Schwartzkopff wrote: > > Ben Timby schrieb: > >> I am working with a 3 node cluster and using an IPaddr2 resource. The > >> resource is a clone, which implies the use of iptables CLUSTERIP for > >> load sharing. However, with three nodes it seems impossible to get > >> even load distribution on failure. Let me explain. > >> > >> If I use three clones, when a node fails, it's identity is assumed by > >> one of the remaining two nodes. This node now has two of the three > >> clones and thus gets 2/3rds of the traffic. > >> > >> I tried using 6 clones n * (n - 1) and using location preferences so > >> that each node would normally have two clones. When a node fails, in > >> theory, it's two clones would each be assigned to one of the remaining > >> nodes. > >> > >> However in practice, with all 3 nodes running, the clones are > >> distributed uevenly (4 on one node, and 1 each on the other two > >> nodes). And failure seems to result in similarly unbalanced > >> distribution. > >> > >> Would it not be possible for the IPaddr2 resource to simply adjust the > >> number of clones when a node dies? Changing the --total-nodes > >> parameter in the iptables would seemingly be the easiest way to ensure > >> even traffic distribution. I know this would play havoc with sessions > >> (sticky connections), but that is not a problem for me. > >> > >> I have attached my cib.xml, I suspect perhaps my location constraints > >> cannot be defined on clone resources the way I have done it. > > > > Hi, > > > > by the way, CLUSTERIP is a quite experimental target of iptables. For a > > production cluster think about using Linux Virtual Server. It also > > integrates nicely into heartbeat. > > CLUSTERIP and LVS serve very different purposes. > > CLUSTERIP spreads the load across different servers in that heartbeat > cluster. > > LVS spreads the load across different servers outside that heartbeat > cluster.
You could use "localhost" as the target for LVS. So you could build a true HA load balancing cluster from just two servers. Greetings, -- Dr. Michael Schwartzkopff MultiNET Services GmbH Addresse: Bretonischer Ring 7; 85630 Grasbrunn; Germany Tel: +49 - 89 - 45 69 11 0 Fax: +49 - 89 - 45 69 11 21 mob: +49 - 174 - 343 28 75 mail: [email protected] web: www.multinet.de Sitz der Gesellschaft: 85630 Grasbrunn Registergericht: Amtsgericht München HRB 114375 Geschäftsführer: Günter Jurgeneit, Hubert Martens --- PGP Fingerprint: F919 3919 FF12 ED5A 2801 DEA6 AA77 57A4 EDD8 979B Skype: misch42 _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
