Copying a file on the same tape medium

The following method can be used to improve IBM Storage Archive Library Edition performance when it copies a file on the same tape medium.

In general, a copy tool subdivides the source file into many smaller blocks and reads a block from the source file. The copy tool then writes it to the target file, repeating the process until the end of the file is reached. If both the source and target files are on the same tape medium, IBM Storage Archive LE must perform a seek operation before it reads and writes a block. The time that is required by a tape drive to seek is much longer than the time required to stream data. To optimize copy operation performance when the source and destination medium are the same, copy a file out of the medium (for example, to a hard disk drive) and then back to it.

On IBM Storage Archive LE, each tape medium in the library displays as a subdirectory under a root mount point. If a file in a directory under a root mount point subdirectory is copied to another directory under that subdirectory, the file is copied on the same tape medium.