On Mon, Feb 7, 2011 at 9:12 AM, Ted Yu <[email protected]> wrote: > This is a good suggestion. > We also need to consider the situation where source RS is under heavy load, > facing potential GC pause. In this case we shouldn't expect source RS to > carry on too much computation.
Whenever things fail unexpectedly, we can always fall back to the current way of migrating regions (expensive for clients but easier for the server). Note that the problem is also valid if the destination RS is having load / GC issues. But hopefully once we expose proper load metrics, the master will be able to make good load balancing decisions. If the master has information such as QPS per region, latency per region, number of GC cycles per GC type, then it can get a pretty clear picture of the load of each RS and try to even it out. -- Benoit "tsuna" Sigoure Software Engineer @ www.StumbleUpon.com
