Troubleshooting Common Failures in IBM Rational ClearCase

Details: Category: Version Control; By Mindful Chase; 31.Jul; Hits: 17

IBM Rational ClearCase is a powerful version control system used extensively in legacy enterprise environments where complex configuration management and large binary asset tracking are critical. However, teams maintaining ClearCase often encounter issues like view corruption, dynamic view slowness, and VOB access failures. These problems can disrupt development pipelines and delay deployments in regulated industries. This article provides a deep technical guide to diagnosing and resolving high-impact ClearCase issues, ensuring system stability and developer productivity in large-scale setups.

Mindful Chase

Writing Code, Writing Stories

tbd

Experience

tbd

More to Explore

Understanding Common ClearCase Failures

Dynamic View Slowness

Dynamic views are mounted over the MVFS (Multi-Version File System). Slowness may stem from overloaded network storage, view staleness, or improper configuration of the view server process.

Symptoms: File access latency, IDE freeze, failed builds
Impact: Developer friction, CI/CD delays, NFS saturation

View Corruption and Missing Elements

View storage may become inconsistent due to disk issues, unclean shutdowns, or improper use of view-private files. The result is missing checkouts, orphaned config specs, or inaccessible branches.

VOB Mount Failures

VOBs (Versioned Object Bases) may fail to mount if the storage server is offline, permissions are misconfigured, or registry data is stale. The failure halts access to core versioned artifacts.

Architecture Overview and Dependencies

ClearCase Components

VOB Server: Stores versioned data
View Server: Hosts snapshot and dynamic views
Registry Server: Tracks VOB and view locations
MVFS: Kernel module for dynamic view access

Key Dependencies

NFS or SAN storage for VOBs and views
ClearCase ALBD (Atria Location Broker Daemon)
Hostname resolution and Windows services (if on Windows)

Diagnostics and Monitoring

Check ALBD and MVFS Status

cleartool lsview
cleartool lsvob
cleartool lsserver
ls -l /view
cleartool catcs

Ensure ALBD is running:

net start "IBM Rational ClearCase ALBD"

Dynamic View Debugging

Use cleartool setview to enter the view and validate file access
Check for errors in view_log and albd_log
Run ctdoctor on Windows or cleartool checkvob on UNIX to validate configuration

VOB Mount Verification

mount
cleartool mount /vobs/project_vob
cleartool describe -long vob:/project_vob

Verify storage host availability and network reachability:

ping vob_server_hostname
netstat -an | grep 371
rpcinfo -p vob_server

Common Misconfigurations and Root Causes

Stale Views

Views not used for long periods or left open during host shutdowns can corrupt. Snapshot views may desync if used across multiple environments without rebase.

Registry or Storage Path Changes

Changing registry entries or moving view/VOB storage without updating ClearCase registry causes hard-to-diagnose failures.

Antivirus Interference

On Windows, antivirus tools can lock MVFS-mounted files or slow down dynamic view resolution.

Improper Config Spec Changes

Manually editing config specs without validation can cause elements to disappear or show incorrect versions.

Step-by-Step Troubleshooting and Recovery

1. Validate View Integrity

cleartool lsview -long viewname
cleartool describe -long view:viewname
cleartool lsvtree filename
cleartool lsprivate -invob

2. Repair Corrupted Views

Delete and recreate snapshot views
Rebase or reimport config spec from a stable baseline
Remove view-private files blocking updates

3. Remount and Re-register VOBs

cleartool umount /vobs/project_vob
cleartool mount /vobs/project_vob
cleartool register -vob \host\vobstore\project.vbs
cleartool mktag -vob -tag /vobs/project_vob \host\vobstore\project.vbs

4. Clean View-Private File Conflicts

cleartool ls -rec -view_only | grep -i .keep
find . -name "*.contrib" -delete

5. Restart ClearCase Services

Restart ALBD and MVFS modules
Ensure hostname resolution (especially on Windows)
Restart view_server or reboot dynamic view clients

Best Practices for Long-Term ClearCase Stability

Automate regular VOB backups and use cleartool protectvob
Set TTLs on stale views and archive unused ones
Schedule checkvob and checkview runs monthly
Use consistent config spec templates with version baselines
Avoid dynamic views in build pipelines—use snapshot or UCM streams

Conclusion

ClearCase is complex but reliable when maintained diligently. Issues like view corruption, slow dynamic performance, and inaccessible VOBs can cripple development pipelines if left unchecked. With targeted diagnostics, proper configuration hygiene, and scheduled maintenance, teams can keep ClearCase stable even in high-regulation environments. Migrating away from ClearCase should be considered long term, but robust troubleshooting and best practices ensure continuity today.

FAQs

1. Why is my dynamic view extremely slow?

Likely causes include MVFS contention, high network latency, overloaded view servers, or antivirus scans. Consider switching to snapshot views for performance-critical operations.

2. How do I detect orphaned views?

Use cleartool lsview -long and compare with actual storage directories. Orphaned views appear in registry but point to missing directories or hosts.

3. Can ClearCase views be shared across hosts?

Snapshot views can be copied with care, but dynamic views are host-dependent. Shared use without rebasing or updating leads to corruption.

4. What causes VOB mount failures after a reboot?

Missing registry entries, unmounted network storage, or ALBD not running can cause VOBs to fail mounting. Always validate service and network layer readiness post-reboot.

5. Is there a way to modernize ClearCase without full migration?

Yes. Introduce a hybrid model with Git for new modules while keeping ClearCase for legacy code. Use scripting to sync snapshots to Git where feasible.

Contact Us