Solution summary

The solution is to relax the requirement that Device Sets must contain a number of Slicestors that is an integer multiple of the IDA Widths of the vaults deployed to them. UnderConcentrated Dispersal, the system now also supports a number of Slicestors that is an even divisor of the IDA Width of the vaults deployed to them.

The previous restriction, which guaranteed that there was one distinct Slicestor behind every pillar (or several in the case of multiple stripes), was put into place to ensure maximum data reliability and availability by ensuring each Slicestor received only one slice of a given source. This maximizes failure independence. In removing this restriction and allowing a single device to be responsible for multiple Pillars will lead to systems that are less available (all else being equal). However, the greater flexibility this affords in selecting optimum IDA configurations means reliability can be maintained if not improved when compared to low-IDA Width (8 and 9 wide) systems in deployment today.