Storage Duration for Surveillance 2012By John Honovich, Published Apr 14, 2012, 08:00pm EDT
How long should video surveillance be stored? 1 week, 1 month, 1 year? This is a fundamental question for security systems. Store for too short a time and you could lose critical evidence yet record too long and it could waste a huge amount of money.
In this report, we share in-depth survey results of security integrators from around the world, examining how long and why real world deployments choose to store surveillance video.
This is part of our unique series on storage fundamentals, helping users make the right decision on the surveillance designs. Related reports include:
- Selecting the Right Frame Rate for Recording
- How to Calculate Surveillance Storage
- Favorite Surveillance Storage Type
- Storage Redundancy / RAID Usage
- Continuous vs Motion Based Recording
The most common storage duration, by far is 1 month; The next most common is 2 weeks. The histogram below charts the breakdown of integrator responses:
While that's the big picture, we captured many nuances in our survey results, allowing us to answer important questions such as:
- Why do customers choose a specific storage duration?
- How does use of megapixel impact storage duration?
- Do larger projects average lower or higher storage duration lengths?
- How long are the longest storage durations?
- What drives long storage durations?
- What markets are most likely to have extreme storage duration requirements?
Drivers of Storage Duration
Three core drivers impact storage duration:
- How long it takes for a user to know that surveillance video is needed? Do they know within a few hours (e.g., an assault or a burglarly) or might it take weeks (e.g., reporting a fraudulent bank transaction)?
- How long does it take to retrieve video? Even if the organization gets the alert within a day or two, they might not be able to retrieve the video for some time. As one respondent noted, "Nobody wants to race a clock inregards to keeping recorded surveillance"
- How much it costs? With most surveillance systems, surveillance storage costs scale linearly (i.e., if the first month costs $10,000 for storage so does the second, third, fourth, etc.). However, the likelihood that video is needed keeps decreasing over time.
Most incidents are generally known within a few days or a week. Add an extra week for retrieval and that gives 2 weeks of storage. This seems to be the minimum generally accepted. With the clear majority of respondents, 1 month was preferred to provide a margin of error.
Many respondents explained that 2 weeks to a 1 month was an acceptable compromise between maximizing availability and constraining storage costs:
- "Good balance between too short and too long of a duration"
- "Good mix of storage requirements and typical incident retrieval time."
- "Most of it is due to budget restrains where they can't afford the storage upfront for months of storage. A good chunk of our jobs, the client will know fairly quickly something has happened and only need a few days of record time."
- "Tradeoff of in price (storage) vs necessity."
- "About 2 weeks. Because is seems to be enough time to find any incident. Most reckon that if they have not need it by the they will not."
However, in the maximum storage duration section below, we examine 4 cases where 2 weeks to a month are not sufficient.
A number of European respondents explicitly cited restrictions on storage for more than 1 month:
- "1 month which is the maximum allowed by the Greek law."
- "We have a law in Sweden saying no longer than 30 days."
- "In France they also have a "decret" that limit keeping the files for more than 30 days."
Max / Longest Storage Duration
For most integrators, none of their projects required more than 2-3 months maximum of storage duration, as shown in the histogram below:
Four common themes emerged for applications requiring long storage duration:
- Government regulations
- Police / Prisons
- Long term litigation concerns
Government requirements are one of the most common drivers:
- "90 days, due a goverment contract, to record behaviour of a 3rd party team inside a goverment building"
- "90 days. It is a federal requirement to capture the data for Federal purposes."
- "90 days. Mandated by the government"
- "90 days ,as govt regulations"
- "90 days. Government mandate involving detention facility."
- "FDA is requiring 180 days worth of video on certain lines."
- "Six months. FDA compliance."
- "6 months. They have been instructed to keep it that long by the Exec Director of their particular agency."
- "Government usually requires up to 6 months of recordings for their archives"
Similarly, police and prisons have long requirements:
- "The longest duration we have is for a police department that records video and audio in their interview and interrogation rooms. That video is recorded manually and is saved until it is manually deleted. By default in the VMS, we set the retention time to 999 days which is the maximum."
- "7 years - A military detention center"
- "Have one correctional facility that archives 1 year ... Reason is for potential litigation defense which has a one year statue of limitations."
- "Two years for holding cells and prisons. It allowed them to defend against any claims of assault or wrongdoing during an inmate's stay. Two years is the statute of limitations."
Banks are the other major sector with consistent requirements for long term storage:
- "all our financial installations are ready for 90 days"
- "90 days. Banking regulations."
- "180 days, banks"
- "120 days. They are a bank and feel that 120 days should suffice for disputes"
- "In india as per bank norms back up should be 90 days available in recorder all time."
- "ATM transactions - regulatory requirements."
- "6 months, corporate compliance issues. Finance."
- "One year for banks, to comply with Central Bank requirements." (Middle East)
Finally, organizations that face significant litigation risk that might not arise for a long time after the incident frequently required long durations:
- "in excess of 6 months. The facility is a Long Term Care provider and that was the length of time that they were able to buy with the budget they gave us for hard drives."
- "We have one who uses 6 months storage, purely becuase cases might not be brought to thier attention for that time ... to prove what type of vapour is being emited and often this won't be brought to thier attention for a long time afterwards."
- "Three years. Apparently, that is the statute of limitations for a personal injury claim, and their Risk Manager has decided that storing that much video is more cost effective that the potential payout that may come from not being able to substantiate the claim."
- "One of our customers is a multinational pharmaceuticals corporation and they keep a record of 2 years .... full record of information (they store all sorts of data regarding their business for even longer time) for possible future reference since they face lots of legal pressures. "
- "Several months. They have specific machinery that is not used very often and sometimes comes up damage or missing several months later."
- "A slip and fall incident happens and 45-100 days pass then a cleint gets a letter from xyz law firm starting that on such and such day ... We are dealing with this exact case now as the cleint is needing to bump up their video backlog to 6 months"
- "A Chemical Manufacture and research facility at five years of storage. They know that most plaintifs lawyers think that most companies keep three years so they wait to file lawsuits until after the video may have been deleated so this customer actually ages their video at different rates."
- "6 months- a food manufacturing plant. Footage is kept for (in the unlikely event) of proving/disproving contamination during manufacturing process."
- "Two years, to be able to track food products back to their manufacturing date if problems are detected during the shelf life of the product."
Impact of Megapixel on Storage Duration
Interestingly, a clear negative relationship appears between storage duration and megapixel usage. The histogram below shows that megapixel heavy projects keep surveillance video for a significantly shorter time:
A few respondents explicitly called out megapixel as a factor in reducing storage duration:
- "With the new systems, they've discovered that the cost of storing 90 days of recording on a 16 camera IP Megapixel system is considerably higher than the 16 channel analog version, they then are willing to go down to 30 days."
- "Most of our clients retain about 30 days of storage, except MP applications (cost) where we achieve about 10 days."
Users are valuing higher quality video over a shorter time frame to keep total storage costs stable.
Impact of Project Size on Storage Duration
Finally, integrators specializing in larger projects clearly kept video for longer time periods than small project specialists:
While this was not explicitly called out in the comments, we suspect that larger camera projects typically have higher security requirements driving the need for longer storage.
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