What bitrate should I assume for NAS capacity planning?
Bitrate varies by codec and resolution: H.264 at 1080p/30fps = 4–8 Mbps; 4K/30fps = 15–30 Mbps. Motion-triggered or variable-bitrate recording averages 30–50% of peak. Use the lower estimate for compliance calculations, then add 20% headroom. See retention math guidance for detailed examples.
Can I use a regular NAS (Synology, QNAP) for surveillance, or do I need surveillance-specific hardware?
Standard NAS appliances work if configured correctly (iSCSI or SMB shares, appropriate RAID), but surveillance-optimized NAS have tuned firmware, larger write caches, and direct VMS integrations. For under 20 cameras or archiving only, consumer NAS suffices; for 40+ cameras or continuous 4K, surveillance-grade appliances reduce support burden and improve reliability.
How long does a RAID 6 rebuild take, and does it affect recording?
Rebuild time scales with capacity: 4TB drives = 12–18 hours; 8TB = 18–30 hours; 12TB+ = 30–48 hours. Performance degrades 20–40% during rebuild. Recording may stall if rebuild I/O starves camera streams. Plan disk replacements during low-traffic windows, use hot-spare pools, or deploy secondary NAS to absorb load.
Should I use iSCSI, SMB, or NFS for my NAS?
iSCSI provides block-level storage, best for high-throughput VMS and snapshots; slightly higher latency sensitivity. SMB/CIFS is simpler, widely compatible, suited for file-based archive and backup. NFS is fast on Linux/Unix systems but less common in Windows-based VMS. Test your VMS with each protocol; most VMS support multiple modes.
What's the difference between RAID 6 and RAID 10 for surveillance?
RAID 6 tolerates two simultaneous disk failures, uses ~67% of raw capacity, but has slower rebuild. RAID 10 (mirrored striping) rebuilds faster, sustains higher throughput, but uses only 50% of raw capacity. For large 12-bay+ systems with long rebuild windows, RAID 6 saves cost; for high-throughput 4K or near-real-time access, RAID 10 is safer.
Do I need 10GbE or is Gigabit enough?
Gigabit (125 MB/s theoretical, ~100 MB/s sustained) suits small sites (under 25 cameras at standard bitrate) or archive-only NAS. 10GbE (1.25 GB/s) is essential for 40+ cameras, 4K streams, or multi-site replication. For medium deployments, bonded Gigabit (2×1GbE = ~200 MB/s) offers a cost-effective middle ground if switch port aggregation is available.