Storage woes: how much is enough?

The prices of storage (price per GB) have been steadily going down for over 30 years. Terabyte drives are now available even to retail consumers. With such cheap prices, one would assume that storage will no longer be a consideration for video surveillance. Yet storage costs are still a fundamental part of surveillance projects, making it important for installers to determine beforehand how much storage would be needed.

Calculating the amount of storage needed
The standard recommendation regarding storage is to use the storage estimators provided by the camera vendors for better accuracy. Many manufacturers offer their own online calculators which often cover storage, bandwidth, power consumption or system requirements. However, considering the number of variable factors involved, a calculator might not be enough.

"The math is actually relatively simple, but there are so many different variables that go into the calculation: camera resolution, frame rate, compression technology, compression level, image complexity (scene activity and lighting conditions), percentage of motion, percentage of recording, and expected retention time. You even have to consider variations across different camera and DSP manufacturers, and whether any of these conditions will change based on an event (i.e., increasing frame rate or resolution during an alarm condition)," explained Brandon Reich, Senior Director of Surveillance Solutions at Pivot3.

Jeffery Huang, APAC Surveillance Sales Manager at Synology, recommends conducting a field test, "In my experience, I often suggest customers to do a minimum viable test to calculate the storage their cameras need under certain circumstances (e.g., day indoor, day outdoor, night indoor, night outdoor). A good option is to record the storage for a day and then calculate according to the needed retention period. By doing this, you can get the amount of storage you need for the project," he said.

A certain "safety buffer" is also recommended for future expansion. "Typically you need to overestimate slightly to have some margins and prepare the storage for growth as the customer usually requests additional cameras when the system is deployed. It might also be possible to use different storage alternatives in a project – critical core cameras can use centralized storage and less important cameras may use cheaper locally attached storage," added Stefan Lundberg, Expert Technologies Engineer at Axis Communications.

Cloud storage as a solution to storage woes?
Cloud storage is emerging as another option that can help users solve their storage challenges. Users can take advantage of the ability to move recorded video from one location to another. For example, a user could decide to record video continuously on-premises and then move only the footage that had an alarm to a central location or to the cloud.

"Cloud storage offers both financial and operational benefits as users don't have to invest in additional IT infrastructure, lessening overall expenditures and decreasing the burden on their IT departments. They also enjoy the flexibility that comes with being able to quickly adjust and increase or decrease their storage demands based on their actual usage. As such, cloud storage offers a number of advantages over traditional storage, with hybrid cloud archiving offering the best of both worlds," said Jimmy Palatsoukas, Senior Product Marketing Manager in Genetec.

However, full cloud storage is still not a viable option for most installations. Especially for installations with a high camera count the cloud is not a viable option due to bandwidth concerns. "Cloud storage is very cheap but bandwidth is still very expensive. Generally speaking the business case is not there for cloud storage and in most territories is a long way off, due to upload bandwidth restrictions, even if costs are ignored," said Alastair McLeod, Group CEO of Veracity UK.