Dynamic mirror service policy with seek adjustment in a non-physical mirrored storage environment

A method for adjusting seek activity in a data storage system of physical devices having mirrored logical volumes comprising:

• collecting statistics describing at least reading data from the mirrored logical volumes during successive time periods;
• determining from the collected statistics an activity level associated with each of the mirrored logical volumes;
• computing seek activity values for the physical devices based on the activity levels associated with the mirrored logical volumes stored on each of the physical devices, the computed seek activity values relating a physical device seek activity to the activity level associated with, and distance between, the mirrored logical volumes residing on the physical devices;
• using the seek activity values computed for the physical devices to minimize seek activity for non-mirrored ones of the physical devices;
• and
• wherein using the computed seek activity values comprises:
• computing a sum of the computed seek activity values;
• performing at least one simulated mirror policy change based on the computed sum of the computed seek activity values;
• recomputing the sum of the computed seek activity values using the results of the at least one simulated mirror policy change;
• determining if the recomputed sum of the seek activity values is less than the computed sum of the seek activity values;
• and
• implementing the at least one simulated mirror policy change.

An apparatus for adjusting seek times in a data storage system of physical devices having mirrored logical volumes comprising

• a stored computer program in memory instituting the steps of
• determining an activity level associated with each of the mirrored logical volumes based on a mirror policy assignment that defines, for each mirrored logical volume and corresponding one of the mirrored logical volumes that mirrors the mirrored logical volume, which mirrored logical volume is preferred to service I/O requests;
• computing seek activity values for the physical devices based on the activity levels associated with the mirrored logical volumes stored on each of the physical devices;
• and
• using the computed seek activity values to change the mirror policy assignment so as to minimize seek activity for non-mirrored ones of the physical devices.

An apparatus for adjusting seek times in a data storage system of physical devices having mirrored logical volumes comprising

• a stored computer program in memory instituting the steps of
• collecting statistics describing at least reading data from the mirrored logical volumes during successive time periods;
• determining from the collected statistics an activity level associated with each of the mirrored logical volumes;
• computing seek activity values for the physical devices based on the activity levels associated with the mirrored logical volumes stored on each of the physical devices, the computed seek activity values relating a physical device seek activity to the activity level associated with, and distance between, the mirrored logical volumes residing on the physical devices;
• using the seek activity values computed for each of the physical devices to minimize seek activity for non-mirrored ones of the physical devices;
• and
• wherein the program instituted step of using the computed seek activity values comprises:
• computing a sum of the computed seek activity values;
• performing at least one simulated mirror policy change based on the computed sum of the computed seek activity values;
• recomputing the sum of the computed seek activity values using the results of the at least one simulated mirror policy change;
• determining if the recomputed sum of the seek activity values is less than the computed sum of the seek activity values;
• and
• implementing the at least one simulated mirror policy change.

A data storage system comprising:

• physical devices having mirrored logical volumes stored thereon;
• a controller for performing a seek adjustment process to adjust the seek activity of the plurality of physical devices, the controller determining an activity level associated with each of the mirrored logical volumes based on a mirror policy assignment that defines, for each mirrored logical volume and corresponding one of the mirrored logical volumes that mirrors the mirrored logical volume, which mirrored logical volume is preferred to service I/O requests, and computing seek activity values for the physical devices based on the activity levels associated with the mirrored logical volumes;
• and
• wherein the controller uses the computed seek activity values to change the mirror policy assignment so as to minimize seek activity for non-mirrored ones of the physical devices.

A data storage system comprising:

• physical devices having mirrored logical volumes stored thereon;
• a controller for performing a seek adjustment process to adjust the seek activity of the plurality of physical devices, the controller determining an activity level associated with each of the mirrored logical volumes and computing seek activity values for the physical devices based on the activity levels associated with the mirrored logical volumes;
• wherein the controller uses the seek activity values computed for the physical devices to minimize seek activity for non-mirrored ones of the physical devices;
• wherein the controller comprises device adapters for performing the seek adjustment process and wherein the controller assigns responsibility for performing different tasks associated with the seek adjustment process to different ones of the device adapters;
• and
• wherein the different tasks are executed in fragments, the size of the fragments being selectable based on the number of logical volumes to be examined during the seek adjustment process.