Patent ID: 9612758
Date: 2017-04-04
CPC Classifications: G06F

Claim:
1. A method of operating data storage equipment, the method comprising: during a first time period and while processing circuitry of the data storage equipment performs host input/output (I/O) operations on behalf of a set of external host computers, performing a data identification operation which provides a data identification result identifying particular data which is routinely accessed by the processing circuitry of the data storage equipment; during a second time period after the first time period and in response to the data identification result, copying the particular data from secondary storage of the data storage equipment to an extension cache which forms part of primary storage of the data storage equipment to pre-fetch the particular data from the secondary storage for subsequent use by the processing circuitry; and during a third time period after the second time period and while the processing circuitry of the data storage equipment performs further host I/O operations on behalf of the set of external host computers, accessing the particular data from the extension cache which forms part of the primary storage of the data storage equipment, wherein the primary storage includes random-access memory (RAM); wherein the extension cache resides in the RAM; wherein performing the data identification operation includes: measuring host I/O operation statistics while the processing circuitry performs the host I/O operations on behalf of the set of external host computers, and identifying the particular data based on the host I/O operation statistics which were measured while the processing circuitry performed the host I/O operations on behalf of the set of external host computers; wherein the secondary storage of the data storage equipment includes an array of storage devices which stores multiple logical units of storage (LUNs); wherein measuring the host I/O operation statistics includes collecting respective host I/O activity metrics for the multiple LUNs over a series of days of the first time period; wherein identifying the particular data based on the host I/O operation statistics includes selecting a particular LUN of the multiple LUNs based on the respective host I/O activity metrics which were collected over the series of days; wherein selecting the particular LUN of the multiple LUNs based on the respective host I/O activity metrics which were collected over the series of days of the first time period includes: based on the respective host I/O activity metrics, (i) detecting a high host I/O activity trend for the particular LUN which lasts a predefined number of days of the series of days, the predefined number of days being at least two days, and (ii) outputting a particular LUN identifier which uniquely identifies the particular LUN among the multiple LUNs; wherein detecting the high host I/O activity trend for the particular LUN which lasts the predefined number of days of the series of days includes: discovering that host I/O activity for the particular LUN exceeded a predefined high host I/O activity threshold during a particular time of day on each day of the predefined number of days of the series of days; wherein copying the particular data from the secondary storage to the extension cache includes: based on the particular LUN identifier, transferring at least a portion of the particular LUN to the extension cache during the second time period; and wherein transferring at least the portion of the particular LUN to the extension cache during the second time period includes: moving metadata of the particular LUN from the array of storage devices to the extension cache, the metadata being different from host data which is read and written by the set of external host computers.