Premigration percentage

The premigration percentage is the space that is occupied by premigrated files as a percentage of the total file system space. The pmpercentage option of the dsmmigfs command sets a target value for premigration.

The default value for the pmpercentage option is the difference between the percentages that you specify for the low and high thresholds. The default cannot be greater than the low threshold.

You can change the value of the pmpercentage option at any time.

When the premigration percentage is configured manually, the low threshold cannot be set to a value smaller than the premigration percentage.

If the percentage that you specify for the low threshold is the same as the percentage for the high threshold, the default premigration percentage is 0. The space management client does not premigrate any files after threshold or demand migration completes.

On IBM® Storage Scale file systems, you can use the IBM Storage Scale policy engine to monitor space thresholds and search for migration candidates.

For information about configuring IBM Storage Scale integration with the space management client, see Technote 7018848.