The video surveillance industry has changed over the past three decades. Analogue images are no longer taken and stored on physical VHS tapes. Today, high resolution, color images are captured and stored instantly onto hard drives, often with directives that mandate retention of footage for a period of months if not years. This makes the use of a reliable high performance Storage Area Network (SAN) more important than ever before in order to prevent loss of video footage.
However, to remain competitive in the face of this challenge, surveillance companies need to reduce the cost of their storage while increasing capacity, reliability and performance. This is even further complicated for some companies who are under strict regulation to hold onto data for extended periods. While holding down costs is important, what lies at the heart of the surveillance is reliability and this is why data security and integrity are more crucial for the surveillance industry than anything else. Here are the top five functions you should equip your SAN with to perfectly safeguard your video surveillance data.
1) A fully redundant hardware design
The first basic point is that the SAN should be equipped with a fully redundant hardware design to prevent any unplanned downtime in the system. Dual modular redundancy (DMR) hardware, in which components are duplicated, provides security in case one should fail. A well-designed SAN storage array comprises dual power supplies so that, if one fails, the other one is ready to carry on the work, and importantly, dual RAID controllers for full protection. It should also have hot swap components, which allow elements to be replaced without significantly interrupting the system. This forms the basis of a sound SAN and reduces the risk of interruption or data loss, under any circumstance.
2) An active-active RAID configuration
RAID’s data redundancy provides a full fail-safe against any kind of hardware failure. Having dual RAID controllers is essential, but equally important is having the right configuration. The ultimate dual RAID controller configuration is known as active-active, which means that the standby controller can immediately take ownership of all drives within the RAID configuration and take over host requests in the event of a controller failure. Many systems only use an active-passive configuration which means that the standby controller has several housekeeping tasks to perform before it can assume responsibility for data I/O which results in degraded performance and the potential for dropped frames in the video footage.
3) A battery-free RAID cache backup mechanism to safeguard data in the event of a power outage
Cache batteries are a service nightmare and only hold unwritten video footage for 72 hours at the very most in the event of a power outage! Batteries degrade over time which reduces their capability to maintain power to a RAID controller for long enough to write any data held in cache memory onto the hard drives for permanent storage. Storage arrays that use batteries for cache power outage protection require regular service to replace cache batteries which is not only an additional cost but may result in downtime or degraded performance during this maintenance. Look for systems which use super capacitor technology to maintain power during an outage coupled with flash card memory to permanently store any unwritten video footage until mains power is restored.
4) Use storage arrays with demonstrated 99.999% availability
Five nines availability (99.999%) is achieved through a combination of high reliability, measured by the Mean Time Between Failures (MTBF) of the system, subsystems and software, and rapid repair of any failure, measured by Mean Time To Repair (MTTR). A combination of modular design, a high degree of component redundancy, a well-designed alert system as well as an effective service and support structure all contribute to high availability. This typically results in less than five minutes of unplanned downtime per year.
5) Sufficient capacity or easy expansion
As image resolution increases, there is a constant need for more storage capacity, especially in the surveillance industry. Before a system gets close to reaching maximum capacity, there should be an alert and expanding storage capacity should be simple. H.264 compression can reduce file sizes but early alerts before reaching maximum capacity are vital. In addition to alerts, there should always be enough spare capacity to archive at least 30 days of video footage.
source: http://www.surveillance-magazine.com/2015/07/28/top-five-functions-san-needs-safeguard-surveillance-data/
Dennis Mancino HD View 360
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