Also, using more stable measures of request count will help, such as 30 minute rolling averages.
> -----Original Message----- > From: Jonathan Gray [mailto:[email protected]] > Sent: Monday, March 21, 2011 4:23 PM > To: [email protected] > Subject: RE: gauging cost of region movement > > This is an interesting direction, and definitely file a JIRA as this could be > an > additional metric in the future, but it's not exactly what I had in mind. > > One of the hardest parts of load balancing based on request count and other > dynamic/transient measures is that you can get some pretty pathological > conditions where you are always moving stuff around. > > To guard against it, I think we'll need to move to more of a cost-based > algorithm that is taking not just the difference in request counts into > account > but also a baseline "cost" of moving a region. The cost difference in load > between two unbalanced servers would have to outweigh the cost > associated with moving a region. As you say, looking at the number of live > operations to a given region could contribute to the cost of moving that > region, but the best measure for that is probably just looking at request > count (it's all requests that incur a cost, not just active scanners). > > JG > > > -----Original Message----- > > From: Ted Yu [mailto:[email protected]] > > Sent: Monday, March 21, 2011 3:44 PM > > To: [email protected] > > Subject: gauging cost of region movement > > > > Can we add a counter for the number of InternalScanner's to HRegion ? > > We decrement this counter when close() is called. > > > > Such counter can be used to gauge the cost of moving the underlying > region. > > > > Cheers
