Specifying migration attributes
- Whether migration is permitted for the data sets
- When a data set is eligible to migrate from level 0
- When a data set is eligible to migrate from level 1
- To what level a data set is eligible to migrate
The COMMAND OR AUTO MIGRATE attribute specifies whether to migrate
the data sets automatically, by command, or not at all. If you specify
BOTH, both automatic and command migration can occur. If you specify
COMMAND, the data sets cannot migrate automatically, but a migrate
command for individual data sets can cause the data sets to migrate,
regardless of the value specified on the PRIMARY DAYS NON-USAGE attribute.
If you specify NONE, the data sets cannot migrate. The default is
BOTH. 
The COMMAND OR AUTO MIGRATE attribute does
not effect Class Transition processing.
The PRIMARY DAYS NON-USAGE attribute specifies the minimum number of days a data set must remain unused on an SMS-managed volume before it becomes eligible to migrate. Eligibility to migrate does not imply that the data set will migrate the next time that space management occurs. If space management achieves the necessary free space without migrating all the eligible data sets on the volume, space management processing stops when the necessary free space is available. The default for this attribute is two days.
- It specifies the minimum number of days that a data set must be unused before it becomes eligible for migration from level 1 to level 2. This number is the total days not used; it is not days that the data set has actually resided on an ML1 volume. All data sets that are eligible migrate at each level 1 to level 2 migration.
- It indicates what level to migrate to from either level 0 or level 1. A value of 1 to 9999 for this attribute specifies that the data set may migrate first from level 0 to level 1, then from level 1 to the specified ML2 device, either DASD or tape. A value of 0 for this attribute specifies that the data set migrates directly from level 0 to ML2 tape. (If the data set has already migrated to ML1 before the attribute was set to 0, it migrates to the specified ML2 device, either DASD or tape.) A value of NOLIMIT specifies that the data set migrates to ML1 and is not to migrate to ML2.
If the value of LEVEL 1 DAYS NON-USAGE has been met and the data set still resides on level 0, it will migrate directly to ML2.
The default for this attribute is 60.