On 19 March 2012 09:23, Radim Kolar <h...@filez.com> wrote: > >> >> Hi Radim, >> >> The number of virtual nodes for each host would be configurable by the >> user, in much the same way that initial_token is configurable now. A host >> taking a larger number of virtual nodes (tokens) would have >> proportionately >> more of the data. This is how we anticipate support for heterogeneity in >> cluster hardware. > > Yes, but this is good only for random partitioner. For ordered you need to > be able split token space on highly loaded servers. With virtual tokens it > will move load to random node. > What if random node will be also hotspot node? Administration will be more > difficult because you don't know where workload lands after you reduce > number of tokens held by node.
For OPP we envisage an external management process performing active load balancing. The initial token assignment would be random within some user-specified range corresponding to the range of their keys. The load would then be monitored and hot-spots would be moved by reassigning virtual nodes to lightly loaded machines, or introducing new tokens into hot ranges. It makes sense that this would not be a manual process, but there would certainly be more control than just increasing or decreasing the number of tokens assigned to a node. -- Sam Overton Acunu | http://www.acunu.com | @acunu
