Using CA Tape Encryption in Your z/OS Environment › Integrated Compression for Symmetric Key Encryption › Compression and Processing Overhead Considerations

Compression and Processing Overhead Considerations

We recommend that you determine your organization's needs for compression of encrypted files. Because compression adds processing overhead, you must carefully consider the type of compression to apply, which files to compress, and even whether to compress files at all. This is a judgment call that will be different for every installation. Compression is a processor-intensive effort, so you must weigh the benefit of compression against the time and resources it takes to perform compression. Consider the following scenarios to help you determine what method is right for your organization:

• You might have an encrypted file that is critical to your enterprise and you know you want to compress the file. You know it will not fit on one tape if it is not compressed, and you do not want to store it on more than one tape. In this case, compression is worth the overhead.
• You might have a requirement to use only one tape or a minimum number of tapes for storing or distributing the encrypted information. In this case, compression is worth the overhead. If it is to your benefit to send only one tape, and you do not want the file to be written to more than one tape, use compression.
• You might not be concerned that a file runs over to another tape. If it does not matter whether the encrypted file is stored on more than one tape, then compression is not a beneficial option for you.
• You might have a situation where you do not have the time to compress files, such as having a short processing window during non-peak hours for running certain jobs that require encryption. If these jobs go over the window of allotted time, the result can be detrimental to your organization's processing capabilities. If compression adds to the time the job takes, you would not want to use compression at that time.
• You might need to conserve the number of tapes used. If that is a consideration, you could use compression globally on all encrypted files.
• Your file might only use a small portion of the tape, so you are not concerned if it uses more space. In this case, you would not want to use compression.

We recommend that you experiment with the different compression methods and see what your results are. For the hardware compression methods especially, some methods will be more suitable to your needs than others. Use the TBECMPCA utility to identify the best compression algorithm to use. Consider whether performance or compression ratio is most important to you.

For information about the TBECMPCA utility, see the Configuration Guide.

Important! CA strongly recommends that you analyze the impact on your environment before you decide whether to turn on compression for all encrypted tapes.