DFSMShsm uses advanced concepts in data hierarchy not always found in similar
products. The data hierarchy is comprised of the following types of data:
- Active data
- Active data is frequently used and seldom migrated data. The data normally
resides on DASD, for fast access, and is in user format. The DASD containing
active data are called level 0 volumes, and they can be managed by DFSMShsm.
- Low activity data
- Low activity data is sometimes used, but not often. This type of data
is eligible to be migrated by DFSMShsm, or has already been migrated by DFSMShsm,
to a more cost efficient type of storage.
- Inactive data
- Inactive data is data that was dumped or is at the incremental backup
level. Dumps and incremental backups are taken of the active data and of the DFSMShsm control
data sets and journal. These dumps and incremental backups can then be used
to recover data sets, or entire volumes, if they are lost due to damage or
accidental deletion.
Inactive data also includes backups of aggregate groups.
These backups can be transported to a remote site for disaster recovery, or
they can be used for other business purposes.
z/OS DFSMS Introduction
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