Getting to know Dell PowerFlex v3.6.x

Rebalance

When PowerFlex detects that user data is not balanced across devices in the Storage Pool, it initiates a process to restore the balance in which data copies are moved from the most utilized devices to the least utilized.

Rebalance is the process of moving one of the data copies to a different server. It occurs when PowerFlex detects that the user data is not evenly balanced across the fault units in a Storage Pool. This can occur as a result of several conditions such as: SDS addition/removal, device addition/removal, or following a recovery from a failure. PowerFlex will move copies of the data from the most utilized devices to the least utilized ones.

Both Rebuild and Rebalance compete with the application IO for the system resources. This includes network, CPU and disks. PowerFlex provides a very rich set of parameters that can control this resource consumption. While the system is factory-tuned for balancing between speedy rebuild/rebalance and minimization of the effect on the application IO, the user has very fine-grain control over the rebuild and rebalance behavior.