The 2010 introduction of 6G SAS drive technology into the video market has demonstrated significant system advantages over historical SATA drives, including dual port, full duplex, concurrent active channels, robust command queuing and superior error detection and correction. Dual port is important because it provides two redundant paths to every hard drive for increased availability and reliability in case of a single-path failure.
The importance of using 6G SAS drive technology in IP-based physical security solutions cannot be understated. The high I/O workload of network cameras can constantly inundate servers, as client workstations on the other end simultaneously attempt to pull video for review. Both slower speed and SATA drives can cause significant bandwidth issues directly due to the buffering that is required with single-channel data transfer. This lag can result in dropped or frozen frames, video artifacting — which is distortions and other visual inconsistencies resulting from compressing a video feed — and a number of other issues. Mission-critical IP video applications require much greater protection than typical off-the-shelf IT data servers, regardless of size and scope.
The Case for Purpose-Built Storage
Storage of your video in a typical network video solution can be immense. It could entail potentially hundreds of high-resolution cameras capturing as many as 30 frames per second, operating 24x7 for a month or up to a few years.
The most common mistake made is to look at streaming video as just another form of data. The case for purpose-built video storage over traditional data solutions focuses on five key areas:
1.Massive database size needs;
3.Intolerances of system latencies;
4.Constant bit-rate streaming; and
5.Demanding operating environments, such as temperature, vibration, bit-error rate and more.
Because of the intrinsic nature of streaming video, each of these five areas requires a purpose-built approach that takes into account unique needs, capabilities and system demands.
Here are four storage technologies that can be used for IP video retention:
Internal Storage is the most popular and offers the best performance at the best price point. The technology records the video to the internal drives within the server. The drives are protected by RAID 5 or 6 ensuring that if a drive was to fail, no data would be lost. Today’s scalable servers can house up to 240TB, all internal to the server.
Directed Attached Storage (DAS) is used when there is not enough drive space available within the server chassis. Because of its multi-lane SAS connection to the server, DAS performs almost identically to internal storage — the drives are also protected by RAID 5 or 6. Direct Attached Storage can be scaled up to 1120TB from a single server using just 22 rack spaces.
Centralized Storage (iSCSI) is used when your customer wants to store the video in a central location. It allows for multiple servers to send video data across the network to a centralized storage array. While popular in the IT world, this storage technology is not as effective in the video world. The iSCSI storage device is only as fast as the network to which it is attached, regardless of what kind or how many SATA or 6G SAS drives are installed. The storage array design must take into consideration potentially large amount of data — it is crucial that it ingests the total bandwidth from all the servers simultaneously without bottlenecking the storage array.
Edge Storage, or on-board storage, stores audio and video recordings within cameras, typically with an SD card. It is particularly beneficial for mobile security or applications that experience network connection interruptions. Edge storage is an excellent complimentary enhancement to central storage that facilitates comprehensive and seamless video coverage building additional redundancy in the solution.
The Missing Link: Video Optimized Workstations
One often overlooked piece is the client viewing station. The highly demanding needs of video surveillance requires a workstation built for 24/7 performance; however, many times an existing workstation or standard PC specification meant for employees is used as the client viewing station.
Purpose-built workstations for video feature higher level cooling systems, 450 watt and greater power supplies, dual Ethernet adapters (for management), server-grade processors and expanded display capabilities.