Edge recording on Axis and Hanwha cameras

Edge recording is recording to storage inside the camera, usually an SD card, so footage keeps being written when the network or the recorder is down. On a fleet that records to a central VMS, it is the backup that covers the gaps every recorder has: a server reboot, a switch failure, a cut link, a maintenance window. Done well, the footage from the outage ends up back on the recorder’s timeline as if nothing happened. Done badly, the card has been dead for a year and nobody knew.

This post covers how edge recording works on Axis and Hanwha cameras, how the card fails without telling anyone, and how to keep it working across 100 to 500 cameras.

Two ways to use the card

Continuous or scheduled recording to the card. The camera writes its own copy all the time, independent of the recorder. The card holds a rolling window, usually days, and overwrites the oldest footage as it fills. This is the only copy for cameras that have no recorder at all, and a second copy for those that do.

Failover recording. The camera writes to the card only when it loses contact with the recorder. When the connection returns, the VMS copies the outage footage back to the server and fills the gap in the timeline. The card’s write load is low, because it only records during outages, and the footage lands where people search for it.

For a fleet on a VMS, failover recording is usually the better fit. It puts the footage where investigators look, and it spares the card most of the writing that wears it out.

Axis: failover recording with AXIS Camera Station Pro

AXIS Camera Station Pro supports failover recording to the camera’s SD card. Per the AXIS Camera Station Pro user manual, the camera records to the card when it loses contact with the server, and keeps recording until the connection returns or the card is full. With the copy option enabled, the footage is copied to the server after reconnection and shown on the timeline in dark gray. Gaps of one to four seconds can remain around the transitions.

The details worth knowing before relying on it:

• Firmware changes the trigger. On AXIS OS 11.11.42 and later, failover starts whenever contact is lost. On earlier firmware it starts only on an unexpected loss, so a planned server shutdown is not covered. Very short interruptions may not trigger it at all.
• The card has to be there and healthy. No card, a full card, or a failed card means no failover footage.
• One server per camera. Only one AXIS Camera Station Pro server can have failover active for a given camera.
• Copy-back needs bandwidth and correct time. Axis’s troubleshooting guide lists insufficient bandwidth for the copy and camera time drift among the reasons failover footage does not come back. Keep cameras on NTP.

In the camera’s own web interface, the card is managed under System > Storage. Onboard storage settings include retention time, autoformat, write protect, and a wear trigger, with check, repair, and format tools. Status > Storage shows free space and disk temperature. Axis sells surveillance-grade cards with wear-level monitoring, and its edge storage page says they last longer than standard SD cards.

Hanwha: SD card recording and WAVE

On Hanwha Wisenet cameras, SD card recording is configured in the camera’s web viewer under Setup > Event > Storage: select the card as the storage device and turn recording on. Hanwha’s support documentation describes an overwrite option. With overwrite on, the camera deletes the oldest footage as the card fills. With it off, recording stops when the card is full. Hanwha recommends industrial-grade cards or better.

On the VMS side, Wisenet WAVE documents a remote archive synchronization feature: for cameras that record to their own storage, WAVE periodically downloads the archive from the camera into the server’s archive. How it behaves after an outage depends on the camera model and WAVE version, and Hanwha’s own WAVE release notes list a fix for imported archives that could have missing periods after a network disconnection. Treat it as something to test on your camera models, not something to assume.

How edge recording fails quietly

Edge recording is a backup, and backups fail without symptoms until the day they are needed. The common ways:

Failure	How it happens	What you notice
Card missing	Removed during service and never put back; never installed on a replacement camera	Nothing, until an outage leaves a gap
Card failed	Flash failure, corruption, a card that stopped mounting	Nothing on the live view; the storage page reports it if anyone looks
Card worn out	Flash has limited write endurance, and continuous recording uses it up	Errors, then failure, often years after install
Card full, overwrite off	Recording stops when the card fills	Outage footage ends early or is absent
Consumer-grade card	Bought on price for a camera that writes all day	Early failure
Clock drift	Footage is stamped at the wrong time, and copy-back can fail	Footage missing from search, or never copied back
Never tested	Failover configured at install, never exercised	The first test is a real incident

Every row is invisible from the live view and from a simple online check. The camera streams normally whether its card is healthy, worn out, or missing.

A checklist for 100 to 500 cameras

1. Know which cameras depend on a card. List cameras with cards, cameras configured for failover, and cameras that record only to the card. These are the ones where a card failure is a footage failure.
2. Use surveillance or industrial-grade cards. Axis and Hanwha both recommend cards built for continuous writing. Match the card to the camera’s write load.
3. Prefer failover over continuous card recording where a VMS records. Fewer writes, longer card life, and the footage returns to the timeline.
4. Set and act on wear. On Axis cameras, set the wear trigger and replace cards when it fires. On cameras without a wear reading, replace cards on a schedule.
5. Keep clocks synced. Time drift breaks copy-back and search. Camera NTP time sync problems covers the fixes.
6. Test failover once per site, and after major firmware or VMS upgrades. Disconnect one camera from the recorder for a few minutes, reconnect it, and confirm the footage appears on the timeline.
7. Check the card after any service visit. A replaced camera or a reseated card is the most common way a card goes missing.

Watching every card across 500 cameras

Checking card status camera by camera in each web interface does not happen often at 500 cameras, which is why worn and missing cards are usually found during an incident.

MentatNOC watches the card in every Axis and Hanwha camera it manages, continuously. A card that disappears from a camera that had one raises an alert, and cameras designed to run without a card are not flagged. A card that reports a failure raises a high-priority alert. On cameras that report card wear, a card at 80 percent wear raises a warning to schedule a replacement, and at 95 percent an alert to replace it now. Offline cameras and clock drift, the other two things that break edge recording, are caught the same way. It monitors device health, not video. Each card alert names the camera and its site, so the replacement list for a site visit is already written. Why security cameras go offline covers the outages that edge recording exists to bridge.

An integrator sees a missing, failed, or worn SD card as a ticket before the client does, so the tech arrives with a replacement card and bills the trip. See the fleet board and its storage alerts on the interactive demo.