Garbage collection and defragmentation for solid state drives (SSD) and shingled magnetic recording (SMR) drives

A non-transitory computer-readable storage medium storing computer executable instructions that when executed by a computer control the computer to perform a method, the method comprising:

• accessing data to be stored by a process that writes to a tape drive or to a virtual tape library, where compressing the data before writing the data to a shingled magnetic recording (SMR) device has a first data reduction level, a first computing resource cost, or a first energy requirement, and where compressing the data on the SMR device after writing the data to the SMR device has a second data reduction level, a second computing resource cost, or a second energy requirement;
• upon determining that the first data reduction level is greater than the second data reduction level:
• compressing the data before writing the data to the SMR device;
• writing the data to a first contiguous set of overlapping tracks on the SMR device;
• upon determining that the second data reduction level is greater than the first data reduction level:
• compressing the data on the SMR device after writing the data to the SMR device;
• and
• providing the SMR device as a virtual tape library that virtualizes the data as a virtual tape.

An apparatus, comprising:

• a shingled magnetic recording (SMR) drive;
• a memory;
• a processor;
• an input/output (I/O) interface;
• a set of circuits comprising a data access circuit, a data reduction level circuit, a compression circuit, a storage circuit, and a virtual tape library (VTL) circuit;
• and
• an interface that connects the memory, the processor, the I/O interface, the SMR drive, and the set of circuits;
• where the data access circuit is configured to access data to be stored by a process that writes to a tape drive or to a virtual tape library;
• where the data reduction level circuit is configured to:
• compute a first data reduction value associated with compressing the data before writing the data to the SMR drive;
• compute a second data reduction value associated with compressing the data after writing the data to the SMR drive;
• where the compression circuit is configured to:
• upon determining that the first data reduction value is greater than the second data reduction value:
• compress the data before writing the data to the SMR drive;
• upon determining that the second data reduction value is greater than the first data reduction value:
• compress the data after writing the data to the SMR drive;
• where the storage circuit is configured to write the data to a first contiguous set of overlapping tracks on the SMR drive;
• and
• where the VTL circuit is configured to provide the SMR drive as a collective VTL that virtualizes the data as a virtual tape.