CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-235447, filed on Dec. 7, 2017, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to a storage control apparatus.

BACKGROUND

A storage system includes a memory device such as a hard disk drive (HDD) or a solid state drive (SSD) and a server for controlling the memory device, and records and manages a large amount of data that are handled in an information processing.

In addition, a snapshot technology of a copy-on-write method is widely used in the storage system. The snapshot technology creates the state of data of a copy source volume on the storage at a specific time point, as a snapshot. By creating and holding the snapshot, the efficiency of data operation such as a backup may be implemented.

Meanwhile, the data accumulated in the storage remarkably increases with, for example, the increase of data handled in a business or the distribution of the virtual environment. Thus, a technology has been developed for suppressing the increase of the storage capacity.

Related technologies are disclosed in, for example, Japanese Laid-open Patent Publication Nos. 2011-113293, H09-231016, and 2016-167212.

SUMMARY

According to an aspect of the present invention, provided is a storage control apparatus including a memory and a processor coupled to the memory. The processor is configured to create a snapshot of a first volume of a storage device. The processor is configured to deduplicate unupdated data among data of the first volume. The processor is configured to compress the deduplicated data to create compressed data. The processor is configured to store the compressed data in a second volume of the storage device. The processor is configured to select, when the snapshot is created for two or more generations, the second volume corresponding to each of a plurality of snapshots of generations earlier than a predetermined generation. The processor is configured to detect unpopular data from the compressed data existing in the selected second volume based on a reference count of the compressed data. The reference count is a number of references to the compressed data made from logical addresses of the selected second volume and created as a result of the deduplication. The processor is configured to collect and decompress detected pieces of the unpopular data when the number of the detected pieces of the unpopular data is equal to or more than a predetermined threshold value. The processor is configured to combine and recompress the decompressed data to create recompressed data.

The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.

