Why is my OpenClaw VPS running slow with high CPU?

OpenClaw's sessions.json file grows over time as cron jobs add entries with full skillsSnapshot copies. A 28MB sessions.json file forces the gateway to parse massive JSON on every operation, causing 60-70% CPU usage and timeouts.

How do I check if sessions.json is causing OpenClaw slowness?

Run 'du -h /root/.openclaw/agents/main/sessions/sessions.json' to check the file size. If it's over 10MB, it's likely causing performance issues. Also check for .tmp files with 'ls -la /root/.openclaw/agents/main/sessions/*.tmp'.

How do I fix OpenClaw session lock timeout errors?

Session lock timeouts occur when sessions.json is too large to read/write quickly. Fix it by: 1) Removing stale .tmp files, 2) Deleting old session files older than 7 days, 3) Removing redundant skillsSnapshot entries from cron runs, 4) Restarting the gateway.

How much CPU should OpenClaw normally use?

A healthy OpenClaw installation should use around 15-25% CPU when idle. If you're seeing 60-70% CPU constantly, it's likely due to session bloat that needs cleanup.

How often should I clean up OpenClaw sessions?

Monitor sessions.json size periodically. If it exceeds 10MB, run the cleanup steps. Consider setting up a weekly cron job to delete session files older than 7 days automatically.

Why Your OpenClaw VPS Is Sluggish (And How to Fix It in 5 Minutes)

Your OpenClaw installation has been running great for weeks. Then suddenly: everything feels slow. Commands take forever. Cron jobs start failing. You check top and see openclaw-gateway eating 60-70% CPU doing... nothing?

I just fixed this exact problem today. Here's what causes it and how to fix it in about 5 minutes.

The Symptoms

You might notice some or all of these:

High CPU usage — openclaw-gateway consuming 60-70% CPU constantly
Slow responses — even simple messages take 10-30 seconds to get a reply, when it should be instant
Memory creep — memory usage at 20% (1.6GB) when it should be ~5%
Lock timeout errors in your cron jobs

Error: timeout acquiring session store lock

If you're seeing this error, keep reading — your sessions.json file is almost certainly bloated.

The Root Cause: Session Bloat

Every time a cron job runs in OpenClaw, it creates a new entry in sessions.json with a full copy of the skillsSnapshot field. Each snapshot is about 3.7KB of JSON.

🔍 The Math

4,767 cron runs × 3.7KB = 21MB of redundant data
Every session operation must read/parse this entire 28MB file.

When the file gets too large:

Every read/write operation takes longer
Write operations timeout before completing
Orphaned .tmp files accumulate
Lock acquisition fails, causing cron job crashes

Step 1: Diagnose the Problem

First, confirm this is actually your issue. Run these commands:

1Check CPU usage

top -bn1 | head -20
ps aux | grep openclaw
    

Look for openclaw-gateway at 60%+ CPU.

2Check sessions.json size

du -h /root/.openclaw/agents/main/sessions/sessions.json

If it's over 10MB, you've found the problem.

3Count session files

find /root/.openclaw/agents/main/sessions/ -name "*.jsonl" | wc -l

Thousands of session files? Time to clean up.

4Check for stale temp files

ls -la /root/.openclaw/agents/main/sessions/*.tmp

If you see .tmp files, these are failed write operations that never completed.

Step 2: The 5-Minute Fix

⚠️ Before You Start

These commands will clean up old session data. Active sessions won't be affected, but you may lose history for sessions older than 7 days.

1Remove stale temp files

rm -v /root/.openclaw/agents/main/sessions/sessions.json.*.tmp

2Delete old session files (>7 days)

find /root/.openclaw/agents/main/sessions/ -name "*.jsonl" -mtime +7 -delete

3Remove skillsSnapshot bloat from cron runs

This is the big one. Run this Node.js script to strip redundant data:

node -e "
const fs = require('fs');
const sessionsFile = '/root/.openclaw/agents/main/sessions/sessions.json';
const data = JSON.parse(fs.readFileSync(sessionsFile, 'utf8'));

let removed = 0;
for (const [key, value] of Object.entries(data)) {
  if (key.includes(':run:') && value.skillsSnapshot) {
    delete value.skillsSnapshot;
    removed++;
  }
}

fs.writeFileSync(sessionsFile, JSON.stringify(data, null, 2));
console.log('Removed skillsSnapshot from', removed, 'cron run entries');
"
    

4Restart the gateway

pkill -f "openclaw-gateway"

The gateway will auto-restart. Give it 10-15 seconds.

5Verify the fix

# Check new file size
du -h /root/.openclaw/agents/main/sessions/sessions.json

# Check CPU usage
ps aux | grep openclaw-gateway | grep -v grep | awk '{print "CPU: "$3"% MEM: "$4"%"}'
    

The Results

Here's what happened when I ran this fix today:

Metric	Before	After
CPU Usage	60-70%	19%
Memory	20% (1.6GB)	4.5% (360MB)
sessions.json	28MB	2.5MB
Load Average	0.81	0.31
Response Time	Slow	Instant

✅ That's It

Your OpenClaw should now be running fast again. The whole fix takes about 5 minutes.

Quick Health Check Command

Save this as a script for easy monitoring:

echo "=== OpenClaw Health Check ===" && \
echo "CPU/MEM:" && ps aux | grep openclaw-gateway | grep -v grep | awk '{print "  CPU: "$3"% MEM: "$4"%"}' && \
echo "sessions.json:" && du -h /root/.openclaw/agents/main/sessions/sessions.json && \
echo "Session files:" && find /root/.openclaw/agents/main/sessions/ -name "*.jsonl" | wc -l && \
echo "Temp files:" && ls /root/.openclaw/agents/main/sessions/*.tmp 2>/dev/null | wc -l
    

Prevention: Keep It Clean

To prevent this from happening again:

Monitor sessions.json size — if it exceeds 10MB, run cleanup
Set up a weekly cron job to delete session files older than 7 days
Watch for symptoms — slow responses and high CPU are early warning signs

      📋 Signs You Need Cleanup
      sessions.json over 10MB
CPU consistently above 40% when idle
Session lock timeout errors
Multiple .tmp files in the sessions folder

    

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Key Takeaways

Session bloat is the #1 cause of sluggish OpenClaw performance
The skillsSnapshot field accumulates in cron run entries
Clean up with a simple Node.js script + file deletion
Monitor sessions.json size — stay under 10MB
The fix takes 5 minutes and dramatically improves performance

Why Your OpenClaw VPS Is Sluggish