Using a NAS to Record Your Security Cameras: How Much Storage You Need

Tiny microSD cards inside security cameras fill up fast and fail quietly, which is exactly why serious setups move their footage onto a NAS. A network drive pulls in every camera stream over your home network, keeps weeks of recordings on proper swappable hard drives, and puts it all in one searchable place. The first question everyone asks is the practical one: how much storage do you actually need? The answer hinges on resolution, camera count and how long you want to keep footage.

Quick Answer

A NAS records IP camera streams over ONVIF or RTSP using a surveillance app, and roughly 512GB holds about 21 days of continuous 4K footage from a single camera. Multiply that by your camera count and your retention target, then add headroom. For a typical four-camera home you are looking at several terabytes.

How a NAS records your cameras

The mechanism is straightforward once you see it. Modern IP cameras broadcast their video as a network stream using standards called ONVIF and RTSP. A surveillance application running on the NAS, the major brands each have their own, connects to each camera's stream and writes it to the drives. Because the NAS pulls the feed itself, the cameras no longer need their own onboard storage, and you get centralised recording, playback and motion search from one interface.

The advantage over in-camera microSD cards is night and day. Instead of a few days of footage on a card that can corrupt or be stolen along with the camera, you get weeks of recordings on full-size drives sitting safely inside, with the option to mirror data across drives for redundancy. You can see the range of suitable hardware in the network storage and smart home section at Evetech.

Choosing a surveillance app for your NAS

The two most common NAS platforms for home use are Synology and QNAP, and both ship their own capable surveillance software. Synology Surveillance Station supports over 8,300 validated camera models thanks to broad ONVIF compatibility, and QNAP's QVR Pro covers more than 200 camera brands with RTSP and ONVIF support. Both offer live view, motion-triggered recording, playback, and alarm notifications.

One important detail: Synology limits free camera licences to two cameras regardless of NAS model. Additional cameras require paid licences. QNAP includes eight free camera licences with QVR Pro. If you are connecting more than two cameras, factor the licence cost into your NAS budget when comparing platforms.

Any camera that supports ONVIF or RTSP will connect, but cameras that rely entirely on a proprietary cloud app without those standards cannot be integrated into a NAS workflow. For a new build, confirm ONVIF support before buying cameras.

Working out how much storage you need

Start with the single-camera baseline: about 512GB stores roughly 21 days of continuous 4K from one camera. From there, three factors scale your number up or down.

Resolution

4K is the heaviest. Drop a camera to 1080p and the same storage stretches far further, often two to three times the retention for the same space. If a camera covers a low-detail area like a passage, recording it at a lower resolution saves significant room without losing what matters.

Camera count

Storage scales close to linearly with cameras. Four 4K cameras recording continuously need roughly four times the single-camera figure, so a 512GB-per-camera rule of thumb points you toward around 2TB just for three weeks of footage, before headroom.

Continuous versus motion recording

Recording only on motion can slash storage dramatically for cameras that watch quiet areas, since most of the day produces no footage. Busy entrances may still warrant continuous recording, but a mix of modes across your cameras is the most efficient setup.

The codec question: H.264 versus H.265

The compression standard your cameras use has a larger effect on storage than most people realise. H.264 is the older standard and still common, but H.265, also called HEVC, compresses the same footage at roughly 30 to 50 percent better efficiency. In practical terms, a 4K camera recording in H.265 uses about half the bitrate of the same camera in H.264, meaning the same drives store roughly twice the footage.

For a four-camera setup this difference is material. If your cameras support H.265, enabling it in their settings before sizing your drives can halve the storage bill. Check your camera firmware and your NAS surveillance app, since both sides of the pipeline need to support the codec for it to work end to end. Newer Synology and QNAP units handle H.265 decoding natively, so playback stays smooth.

Sizing a real four-camera home

Put it together for a common scenario: four cameras, a mix of 4K and 1080p, around three to four weeks of retention. With H.264, that lands most homes in the 4TB to 8TB range. With H.265 on all cameras, the same setup drops to roughly 4TB to 6TB. Buying NAS-rated drives at that size leaves room to add a camera later without re-planning. NAS-rated drives matter here because they are built for the constant write load that surveillance recording demands, unlike ordinary desktop drives.

Plan for at least two drive bays so you can mirror footage for resilience, and you have a setup that survives a single drive failure without losing your recordings. A NAS with mirrored 4TB drives gives you 4TB of usable surveillance storage with full redundancy, covering most home setups comfortably.

To keep the build tidy, the cabling, mounts and spares you will need around it sit in the accessories range at Evetech.

Frequently Asked Questions

How much footage does 512GB hold?

Roughly 21 days of continuous 4K recording from a single camera. Lower resolutions or motion-only recording stretch that figure considerably, and more cameras divide it proportionally.

What are ONVIF and RTSP?

They are the networking standards IP cameras use to broadcast their video. A NAS surveillance app connects to each camera over ONVIF or RTSP and writes the stream to its drives, so the cameras need no onboard storage.

Do I need special drives for a NAS surveillance setup?

Yes, use NAS-rated drives. Surveillance recording is a constant write load that ordinary desktop drives are not built for, so purpose-made drives last far longer in this role.

Can recording on motion only save storage?

Significantly, for cameras watching quiet areas. Most of the day produces no recording, so motion-only mode can multiply your retention. Busy entrances may still justify continuous recording.

Is a NAS better than recording to a microSD card in the camera?

For anything beyond a single camera, yes. A NAS centralises weeks of footage on swappable drives, offers redundancy, and keeps recordings safe even if a camera is stolen, which a microSD card cannot.

Do I need to pay for camera licences on a NAS?

It depends on the platform. QNAP includes eight free camera licences with QVR Pro. Synology limits free licences to two cameras and charges for additional ones. Factor the licence cost into your platform choice if you plan to connect more than two cameras.

Does H.265 make a meaningful difference to storage?

Yes. H.265 compresses footage at roughly 30 to 50 percent better efficiency than H.264, which can halve your storage requirement if your cameras support it. Check both camera firmware and your NAS surveillance app to confirm end-to-end H.265 support before relying on those savings.