Space ABENDS - S37/SB37/SD37 Resolution Strategy

"Our end-of-month reconciliation job (40-step process) consistently ABENDs with space issues:

• Month 1: SD37 at Step 22 (output file)
• Increased secondary allocation, ran successfully
• Month 2: SB37 at Step 28 (different file, same volume)
• Moved to larger volume, ran successfully
• Month 3: SD37 again at Step 22 (same file as Month 1)

File characteristics:

• Dataset: MONTHLY.RECON.DETAIL
• Current allocation: PRIMARY=CYL(500,100), 15 secondary extents allocated
• Volume: DISK03 (3390-27, 70% full)
• File grows ~15% month over month
• Must keep for 7 years (regulatory requirement)

Design a sustainable solution. Consider costs, performance, and future growth."

• Understanding of different space ABEND types
• Capacity planning skills
• Cost-benefit analysis
• Long-term architecture thinking
• Knowledge of SMS and storage management

1. Immediate Diagnosis:

• SD37: Maximum 16 extents reached (primary + 15 secondary)
• SB37: Volume full, no more space available
• Root cause: Poor initial allocation + monthly growth

2. Short-term Fix (This Month):

• Reallocate with larger primary: CYL(1000,200) [accommodates 2 months growth]
• Use IEFBR14 to delete/redefine or IDCAMS REPRO to new allocation
• Move to volume with more free space

3. Long-term Solution:

• Option A: Implement SMS with storage classes
• Automatic volume selection
• Space management policies
• Let system handle allocations
• Option B: Convert to VSAM (better space management)
• Option C: Archive older months to tape/cheaper storage
• Keep 3 months online, rest archived
• Regulatory compliance maintained

4. Capacity Planning:

• Growth rate: 15% monthly = 180% annually
• Calculate: Current size × 1.15^12 months
• Allocate for 18-month growth to reduce maintenance

5. Monitoring:

• Set up alerts at 80% space utilization
• Monthly review of dataset growth trends
• Automate space reporting

• ❌ Just says "allocate more space" without analysis
• ❌ Doesn't differentiate between SD37, SB37, S37
• ❌ Doesn't consider 7-year retention requirement
• ❌ No mention of cost implications
• ❌ Ignores SMS as an option

• "What's the maximum number of extents for a dataset?"
• "How would you calculate the current dataset size from the allocation parameters?"
• "What if the business says they need 10 years of online data?"
• "How does SMS help with space management?"