Configuring Bin Size

The number of bins used by the disk balancer is not constant and is determined by the sizes of different bins. You can configure the size of each of the bins (Below Average, Average, Above Average, and Overused) individually at run time. The larger the size of the bins, the greater the chance that two SPs that are in the vicinity of each other with respect to utilization fall in the same bin.

The default size of overused bins is only 3%, because SPs in this bin must be balanced at a finer granularity. The default size of above average, average, and below average bins is 20%. You can aggressively balance the storage pools across bins by reducing the size of each bin, forcing the SPs to fall into different bins. To reduce the size of each bin, specify the value for the following parameters using the maprcli config save command:

Parameter Description
dbal.above.avg.bin.size Specifies the bin size (%) of SPs whose usage is above the cluster average. The default is 20%.
dbal.avg.bin.size Specifies the bin size (%) of SPs whose usage is in the average range. The default is 20%.
dbal.below.avg.bin.size Specifies the bin size (%) of SPs whose usage is below the cluster average. The default is 20%.
dbal.overused.bin.size Specifies the bin size (%) of SPs whose usage is in the overused range. The default is 3%.

For example, to reduce the size of the Below Average bin to 10%, run the following command:

maprcli config save -values {"dbal.below.avg.bin.size":"10"}