FIELD

This disclosure relates to computing systems and related devices and methods, and, more particularly, to a method and apparatus for identifying high importance devices of a consistency group.

SUMMARY

The following Summary and the Abstract set forth at the end of this application are provided herein to introduce some concepts discussed in the Detailed Description below. The Summary and Abstract sections are not comprehensive and are not intended to delineate the scope of protectable subject matter, which is set forth by the claims presented below.

All examples and features mentioned below can be combined in any technically possible way.

A consistency group is defined to include a set of required devices on a set of storage systems. High activity devices are determined, and write dependencies between each high activity device and each of the low activity devices are monitored. A set of high importance devices is determined to include the high activity devices and low activity devices with a high write dependency on at least one of the high activity devices.

In some embodiments, the write patterns on each of the high activity devices are monitored and write patterns on each of the low activity devices of the consistency group are monitored. Pairs of devices are formed, in which each pair includes one high activity device and one low activity device. Write patterns of the pairs of devices are compared to determine respective percentage coordinated write probabilities for pairs of devices. Write patterns of the pairs of devices are also compared to determine ratios of write operations for pairs of devices. A coordinate write probability above a threshold, or a determined ratio of write operations that occurs sufficiently frequently, is interpreted as an indication that one of the low activity devices is a high importance device.

Once the set of high importance devices is determined, in some embodiments a set of similar data structures are used to compare write probabilities between the high importance devices and other devices (low importance devices) of the consistency group to identify write dependencies between the set of high importance devices and the other (low importance) devices in the consistency group. Low importance devices in the consistency group that do not exhibit write dependency with any of the high importance devices are candidate devices for removal from the consistency group. A learning process is trained and used to analyze the write patterns to select candidate devices for removal from a consistency group.

Once the high activity devices are determined, the write patterns on the high activity devices can also be compared with write patterns of devices outside of the consistency group to determine candidate devices to be added to the consistency group. In some embodiments, the write patterns on each of the devices outside of the consistency group are monitored. Pairs of devices are formed, in which each pair includes one high activity device and one device outside of the consistency group. Write patterns of the pairs of devices are compared to determine respective percentage coordinated write probabilities for pairs of devices. Write patterns of the pairs of devices are also compared to determine ratios of write operations for pairs of devices. A coordinate write probability above a threshold, or a determined ratio of write operations that occurs sufficiently frequently, is interpreted as an indication that one of the devices outside of the consistency group is a high importance device and should be considered for inclusion in the consistency group. A learning process is trained and used to analyze the write patterns to select candidate devices to be added to the consistency group.

