Master NFS Interview Questions: 30 Essential Linux Cloud File System Q&A

Overview

This guide presents 30 high‑frequency NFS interview questions for Linux cloud positions, covering basic concepts, architecture, protocol history, alternative file systems, configuration files, export options, client mounting, security options such as root_squash, UID/GID mapping, NFSv4 improvements, pNFS, performance tuning, troubleshooting steps, RPC diagnostics, high‑availability designs, cloud‑managed NFS services, monitoring, and design considerations.

Key Topics

Fundamentals

Definition, design goals, client‑server model, RPC basis.

Historical origin (Sun Microsystems, 1984) and industry status.

Comparison with SMB/CIFS, AFS, GlusterFS, CephFS, Lustre.

Configuration & Operations

Main export file /etc/exports and common options (rw, ro, sync, async, root_squash, no_root_squash, no_subtree_check).

Applying changes with exportfs -ra or service restart.

Client commands: showmount -e, mount -t nfs -o …, /etc/fstab with _netdev.

Security & Permissions

Impact of root_squash vs no_root_squash.

UID/GID based access control and mismatches.

NFSv4 security mechanisms (Kerberos, RPCSEC_GSS, ports).

Performance & Advanced Features

Compound operations, pNFS architecture, tuning parameters (rsize, wsize, actimeo, noatime, lookupcache).

Port usage (NFSv4 uses fixed TCP 2049).

Troubleshooting & High Availability

Network checks, rpcinfo, service status, firewall rules.

Force unmount techniques (lazy, hard, combined).

HA solutions: DRBD+Pacemaker, GlusterFS/CephFS, cloud services (AWS EFS, Azure Files, GCP Filestore).

Monitoring & Design

Metrics via nfsstat, system resources, Prometheus/Grafana, alerts.

Design checklist: redundancy, RAID, caching, multi‑path, backup, documentation.