Troubleshooting CPU - I/O : Best linux ps Command Arguments for Troubleshooting - One‑Command “Master View” (Highly Recommended)

 

One‑Command “Master View” (Highly Recommended)

ps -eo user,pid,ppid,stat,%cpu,%mem,etime,lstart,wchan,comm --sort=-%cpu

🔍 What it shows (and why it matters)

Field	Why it’s important
user	Who owns the process
pid	Process ID
ppid	Parent process (helps detect orphans)
stat	Process state (R/S/D/Z/T)
%cpu	CPU consumption
%mem	Memory usage
etime	How long the process has been running
lstart	Exact start time
wchan	Kernel wait channel (I/O diagnosis)
comm	Executable name
--sort=-%cpu	Top CPU consumers first

✅ This is your best single snapshot for general troubleshooting

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2️⃣ CPU Troubleshooting (High CPU / Run Queues)

ps -eo pid,ppid,stat,psr,pri,ni,%cpu,time,comm --sort=-%cpu | head -20

Key columns

Column	Meaning
psr	Which CPU core it’s running on
pri	Kernel priority
ni	Nice value
time	Total CPU time consumed

✅ Use when:

• Load average is high
• CPU is saturated
• Performance complaints

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3️⃣ I/O Troubleshooting (MOST CRITICAL)

🔥 Identify blocked processes (D state)

ps -eo pid,stat,wchan,%cpu,etime,comm | awk '$2 ~ /D/'

Why this is powerful

Field	Purpose
D	Uninterruptible sleep (I/O wait)
wchan	What kernel function it’s stuck on
etime	How long it has been blocked

Common wchan values and meaning

wchan	Meaning
io_schedule	Disk I/O wait
wait_on_page_bit	Memory/disk interaction
nfs_wait	NFS hang
blk_mq_get_tag	Storage queue congestion

🚨 If Oracle or DB processes appear here → storage issue almost guaranteed

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4️⃣ Memory & Leak Detection

ps -eo pid,ppid,stat,rss,vsz,%mem,comm --sort=-rss | head -20

Key fields

Field	Meaning
rss	Real memory in KB
vsz	Virtual memory
%mem	RAM usage

✅ Use when:

• System is swapping
• OOM killer events
• Slow performance despite low CPU

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5️⃣ Full Command, Arguments & Environment

ps -eo pid,stat,%cpu,%mem,cmd --sort=-%cpu

Why this matters:

• cmd shows complete arguments
• Crucial for:
  • Java tuning
  • Oracle startup flags
  • Application misconfiguration

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6️⃣ Zombie Process Detection

ps -eo pid,ppid,stat,etime,comm | awk '$3 ~ /Z/'

Why care?

• Zombies indicate parent process bug
• Can exhaust PID space
• Need parent restart (not kill)

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7️⃣ Oracle / Database‑Focused View (DBA Favorite)

ps -eo pid,stat,%cpu,%mem,etime,wchan,comm | grep ora_

✅ Detects:

• DBWR / LGWR I/O stalls
• Parallel worker hangs
• Backup‑related blockages

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8️⃣ Thread‑Level Analysis (Advanced CPU Debugging)

ps -eLo pid,lwp,stat,%cpu,psr,comm --sort=-%cpu

Use when:

• Java or Oracle shows high CPU
• Need hot thread detection
• Correlating with perf / jstack

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9️⃣ Parent‑Child Relationship Analysis

ps -eo pid,ppid,stat,etime,comm --forest

✅ Great for:

• Detecting fork storms
• Tracing hung parent processes
• Understanding service trees

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10️⃣ Minimal “Health Check” Command (Quick & Safe)

ps -eo pid,stat,%cpu,%mem,etime,comm --sort=-%cpu | head -15

✅ Safe for production
✅ Quick triage
✅ Covers 80% of issues

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🔑 What to Focus On (Cheat Sheet)

Symptom	Look at
High load	%cpu, R state
Stuck system	D state, wchan
Slowness	%cpu, %mem, etime
Hung DB	ora_* + D
Memory issues	rss, %mem
Defunct processes	Z

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✅ Final Recommendation (What to Remember)

If you remember only ONE command, make it this:

ps -eo user,pid,ppid,stat,%cpu,%mem,etime,wchan,comm --sort=-%cpu

This single command gives: ✅ CPU
✅ I/O
✅ Memory
✅ State
✅ Ownership
✅ Runtime
✅ Kernel wait reason