Skills

Remote System Maintenance

Purpose

Structured guidance for diagnosing and maintaining remote Linux systems through SSH/tmux sessions, with emphasis on Ubuntu/Debian platforms.

Applicable Scenarios

• System maintenance tasks
• Disk space recovery
• Package updates
• Health diagnostics
• Cleanup operations on remote servers

Three-Phase Approach

Phase 1: Initial Diagnostics

Capture baseline system state:

• Hostname and system identification
• Resource utilization (disk, memory, CPU)
• Process status and load
• Zombie process detection

Phase 2: System Log Review

Examine system health indicators:

• Recent error messages in system logs
• Journal disk consumption analysis
• Critical service status
• Authentication and security events

Phase 3: Package Assessment

Identify maintenance opportunities:

• Upgradable packages
• Orphaned configurations
• Unused dependencies
• Package cache size

Ubuntu/Debian Cleanup Sequence

Execute these seven stages in order:

1. Package Cache Refresh - apt update to sync package lists
2. System Upgrades - apt upgrade for security and bug fixes
3. Orphan Removal - apt autoremove to clean unused dependencies
4. Cache Purging - apt clean to reclaim package cache space
5. Journal Pruning - journalctl --vacuum-time=7d to limit log retention
6. Snap Revision Cleanup - Remove disabled snap revisions (see below)
7. Temporary Directory Assessment - Review /tmp and /var/tmp for cleanup opportunities

Snap Revision Cleanup Technique

Snap keeps old revisions by default. To identify and remove:

# List all disabled snap revisions
snap list --all | awk '/disabled/{print $1, $3}'

# Remove specific revision
snap remove <package-name> --revision=<revision-number>

Important: Requires explicit removal by revision number, not simple package uninstallation.

Documentation Requirements

All maintenance sessions must generate structured logs recording:

1. System Identification

   • Hostname
   • OS version
   • Kernel information
   • Operator identity

2. Resource States

   • Initial disk/memory/CPU usage
   • Final disk/memory/CPU usage
   • Quantified improvements

3. Actions Taken

   • Specific commands executed
   • MB/GB freed per category
   • Packages upgraded/removed

4. Follow-up Recommendations

   • Remaining issues
   • Future maintenance needs
   • Monitoring suggestions

Expected Results

Real-world recovery examples:

• Journal vacuuming: 300-600 MB
• Snap revision cleanup: 500 MB to 2 GB
• Package cache purging: 100-500 MB
• Total potential: 2+ GB in comprehensive sessions

Time Commitment

Typical maintenance session: 15-30 minutes including diagnostics, cleanup, and documentation.