IBM LTFS Copy Tool
This topic describes the IBM® LTFS Copy Tool, which is a utility that can be used to efficiently transfer data to and from LTFS tapes.
- Ability to copy tape contents with optimum order
- Improved performance for reclamation and defragmentation of a tape medium
- Improved performance for retrieving files from an LTFS-formatted tape medium (when LTFS is built into the tape archive solution)
The IBM LTFS Copy Tool optimizes performance of data transfers through multithreaded operations, memory or disk buffering, and multifile reads from tape that are ordered by location on the tape. These features are described in more detail below.
Multithreaded operation
The IBM LTFS Copy Tool utilizes memory or disk buffering to transfer data, which enables the data to be transferred during a multithreaded operation. This means that while the program running on a thread reads a file on the tape medium or disk to the memory or disk buffer, the program running on another thread writes data from the memory or disk buffer to the medium simultaneously. This mechanism improves the copy performance.
Reordering by location
The files on a tape medium allow sequential access only. If multiple files are copied without reordering, LTFS sequentially seeks files on the medium. For example, if the first file exists next to the second file, LTFS searches for the bottom of the second file and reads it, and then seeks back to the beginning of the first file. This seek operation drastically degrades the multifile copy performance of LTFS. By reordering by location, the LTFS Copy Tool reads the second file, and then reads the first file. This eliminates any unnecessary seek operations and improves the overall copy performance.