Q: What is a `tmpfs` filesystem, and why would you use it in production?
tmpfs is a filesystem that lives entirely in RAM (and optionally Swap). Files stored in tmpfs are never written to physical disk, making ...
#Linux #Linux / SRE — Scenario-Based Interview Questions #L1 #SRE #Systems #Troubleshooting
🎙️ Candidate Opening & Architectural Context
""We encountered this OS-level bottleneck during peak traffic and diagnosed it down to kernel and filesystem metrics. The interviewer is testing: RAM-backed filesystems, volatile storage use cases.. I structure my answer around systematic triage first, root cause analysis second, and permanent remediation third.""
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🛠️ Production Runbook & Step-by-Step Resolution
1️⃣
Initial Diagnostics & Root Cause Analysis
tmpfs is a filesystem that lives entirely in RAM (and optionally Swap). Files stored in tmpfs are never written to physical disk, making read/write operations extremely fast but volatile—all data is lost on reboot.
/tmpand/run: Many distributions mount these astmpfsto speed up temporary file operations and automatically clean them on reboot.- Sensitive secrets: Store decrypted secrets or API keys in
tmpfsso they are never persisted to disk, reducing attack surface. - Build caches: Compilation temp files placed in
tmpfsdramatically speed up build times.
2️⃣
Remediation & Permanent Safeguards
Common production use cases: To create a tmpfs mount: To persist across reboots, add to /etc/fstab:
mount -t tmpfs -o size=512M tmpfs /mnt/ramdisk- Session data: Web server session files written to
tmpfsavoid disk I/O bottlenecks.
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Pro-Tip: /tmp and /run: Many distributions mount these as tmpfs to speed up temporary file operations and automatically clean them on reboo."
⚡ 60-Second Elevator Pitch Talking Points
- /tmp and /run: Many distributions mount these as tmpfs to speed up temporary file operations and ...
- Sensitive secrets: Store decrypted secrets or API keys in tmpfs so they are never persisted to di...
- Build caches: Compilation temp files placed in tmpfs dramatically speed up build times.
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