DFSMS

Data Facility Storage Management Subsystem

Enhanced Definition

IBM's integrated storage management system providing automated space management, backup, migration, and data protection services for z/OS. DFSMS simplifies storage administration through policy-based automation.

Key Characteristics

- Policy-based storage management
- Automatic space and volume management
- Data class, storage class, management class
- Integration with catalogs and VSAM
- Backup and recovery automation
DFSMS Components:
- DFSMSdfp: Data Facility Product (access methods, catalogs)
- DFSMSdss: Dataset Services (backup, restore, copy)
- DFSMShsm: Hierarchical Storage Manager (migration, backup)
- DFSMSrmm: Removable Media Manager (tape management)
- DFSMStvs: Tape Volume Sharing
Storage Management Classes:
- Data Class: Dataset attributes (RECFM, LRECL, etc.)
- Storage Class: Performance and availability requirements
- Management Class: Backup, migration, retention policies
DFSMS Functions:
- Automatic Class Selection (ACS): Policy-driven dataset allocation
- System-Managed Storage (SMS): Automated storage management
- Space Management: Automatic space allocation and release
- Data Migration: Movement between storage tiers
- Backup Management: Scheduled and on-demand backups
ACS Routine Types:
- Data class ACS routine
- Storage class ACS routine
- Management class ACS routine
- Storage group ACS routine

Use Cases

- Automating storage allocation policies
- Implementing tiered storage strategies
- Managing backup and recovery operations
- Optimizing storage utilization
- Enforcing data retention policies