One of the primary functions of any surveillance system is to record video footage, thus allowing forensic analysis should an event occur. Despite video solutions being used in a number of proactive ways, recording remains a key requirement for the vast majority of applications. Whilst diverse archiving methods exist, one of the most popular options is the use of HDDs in servers or NVRs. With the leading hard drive manufacturers offering dedicated surveillance ranges, installers and integrators are now able to specify specialised recording media. With increases in capacity, Seagate now offers the Skyhawk surveillance range, which includes a 10TB drive.
Those who have been in the security industry for some years will remember many of the issues surrounding VHS tape cassettes. Many sites experience problems due to the use (and often the overuse) of cheap tapes. Because of the unusual operational nature of time-lapse VCRs, standard tapes quickly deteriorated and often failed if used in security applications. This resulted in a number of tape manufacturers producing dedicated surveillance VHS cassettes. Back then, installers and integrators working in the video sector quickly learned that using cheaper media was a shortcut to failure.
When digital recording emerged as a credible alternative to tape-based systems, the security industry had to make do with available media. At that time, hard drives were designed for data-based applications, and as such expected workloads were for IT use. Normal usage was based on cycles of occasional reading and writing. Basically an operator would create or edit a file locally, and only when their tasks were complete would that file be saved. Effectively this meant for long periods the hard drives would be inactive.
The issue with surveillance is that cameras streaming video at up to 25 frames per second, for 60 seconds of every minute, for 60 minutes of every hour, 24 hours per day. This means that the hard drives are continually writing data, which was not a task they had been designed for. With no other options in terms of hard drive media, early digital surveillance recorders often failed prematurely.
As hard drive manufacturers made more specialised products available, the surveillance sector was able to benefit from advances in hard drives designed for audio-visual and enterprise networking applications. However, whilst these drives were more robust than those designed for the desktop market, they still struggled with the unusual operational demands of video surveillance.
Thankfully the leading hard drive manufacturers recognised the requirements of the video surveillance sector, and in recent years we have seen the emergence of surveillance-rated HDDs. These drives have been specifically designed, from the ground up, to cope with intensive write cycles. Also, these drives have been optimised to manage high data flows, thus allowing support for multiple HD and 4K UHD video streams.
Today’s video surveillance market is comprised of two distinct layers. The first is made up of innovative and bespoke solutions designed primarily to deliver security and additional benefits to end-users. These systems typically use best-of-breed devices and components to ensure the highest quality combined with longevity in the field. It is these types of systems, championed by Benchmark, there are most likely to include well-considered archiving elements including dedicated surveillance-rated HDDs.
The second layer is made up of systems predominantly designed to a low price. Such systems tend to use basic off-the-shelf devices, and given the cost and lower expectations regarding the product’s lifetime, are more likely to be left with whatever HDD comes fitted as standard.
As such, for forward-looking installers and integrators designing smarter systems to meet evolving end-user needs, the robust and reliable nature of surveillance-rated HDDs will be of great importance. With growing demand for the use of higher resolution HD and 4K UHD video, HDD capacity is also an important issue. To meet such demands, Seagate has launched the Skyhawk range of surveillance HDDs including a 10TB model.
The Seagate Skyhawk 10TB surveillance drive is a 3.5 inch HDD with a SATA 6Gbps interface. The drive can be deployed in bays of eight drives or more; there are a number of surveillance-rated drives which can only be used in bays of up to 8 drives due to issues with vibration. The Skyhawk 10TB has no such issues. This also makes the dry is ideal for use in RAID deployments. Drives can support up to 64 streams due to ATA streaming support, and have a quoted maximum transfer rate of 210MB per second.
Operational time is up to 8,760 hours per year, which equates to 24 hours per day, 365 days each year.
Load/unload cycles are specified as 300,000. The drives are designed to write data for 90 per cent of their operational time. With the workload rating of 180TB/year, the rating significantly exceeds typical desktop drives. Mean time between failures is stated as 1 million hours. Operational power requirement is 6.8W.
One common issue with HDDs used in security applications arises when the surveillance system is used as a standalone solution. This can result in recording servers or NVRs being placed in racks, cupboards or other spaces with insufficient ventilation. Many desktop-type hard drives will degrade or even fail if temperatures exceed 40 degrees C. Where insufficient cooling and ventilation is available, it is not uncommon for this threshold to be exceeded due to a combination of ambient temperature and heat generated by the equipment. The Skyhawk surveillance HDD has a rated case temperature of 70 degrees C, although the manufacturer does not recommend sustained use at temperatures in excess of 60 degrees C. That said, it is best practice to try and ensure that servers and NVRs operates at lower temperatures.
The hard drives also make use of Seagate’s ImagePerfect firmware. This is designed to deliver smooth and consistent streaming, eliminating issues such as drop frames, stutter, lag, etc..
The Skyhawk HDDs supplied with a three year warranty. For increased peace of mind, there is also an option to take out a three-year data recovery plan. If the surveillance footage is vital to risk mitigation on a site, the recovery service is designed to restore data lost due to vandalism, viruses, accidents and other drive failures. Whilst no guarantee is given with regard to the restoration of data, Seagate does claim a 90 per cent success rate.
Installing the Seagate Skyhawk 10 TB HDD is, in effect, the same as installing any other replacement hard drive. The usual provisos with regard to care concerning touching components and ensuring correct earthing to eliminate risks of damage due to static electricity all apply. Connection is via standard SATA links; the relevant connectors should be supplied with the server or NVR. The drive components which enhance performance and reliability are all internal, and for the installer or integrator the process is as with any other HDD.
A manual is available for the hard drives. This is not supplied with the units and needs to be downloaded from the Seagate website. Whilst this contains a host of information that may be of interest if you’re a bit of a hard drive geek, the reality is that you probably won’t need it.
The important issues are to exercise best practice when handling the drives and working around other components, and to ensure when mounting the drive in the server or NVR that the unit is fixed firmly and securely.
When assessing system components such as hard drives, unless you have an out-of-the-box failure, it is unlikely that the drive will do anything but work in the early stages. As a result, this test follows the procedures Benchmark has used with hard drives in the past. The assessment process is therefore made up of four stages.
The first stage, which is covered by this test report, covers running the drive at its full capacity to assess read and write performance. The second and third stages involve using the drive in hostile conditions; these are in environments with artificially exaggerated temperatures and vibration.
The final stage involves creating an end-of-life scenario for the drives to ascertain whether or not the recovery service can restore the data.
Initially the drives were added to a server used for a number of tests and assessments carried out by Benchmark. During use, multiple streams of video including HD, 4K UHD and megapixel video were archived. Typical stream numbers varied between 30 to 40 inputs, although for periods this was extended up to 64 streams in line with the specification of the Skyhawk drives.
During the test period the drives performed as expected, and at no point did we experience any issues or problems with normal operation. Playback was smooth and consistent, and detailed examination of the real-time footage did not show any visible degradation or drop in consistency with regard to image quality. In reality, we wouldn’t have expected to see anything of concern due to the fact we were dealing with a professional quality surveillance-rated set of drives.
In standard use, albeit over a relatively short period of time, the drives performed a specified. It must be noted that the initial assessment was carried out in a clean environment with more than adequate cooling and ventilation. If anything, the situation was more than favourable for optimum operation.
However, the next stages of testing (which have now commenced) will be far more hostile and are designed to accelerate any potential failure. To allow the performance of the Seagate drives to be put into context, the test also includes standard desktop drives and audio-visual HDDs.
The first phase of this long-term test simply serves to establish that the Skyhawk 10TB drives deliver the specified level of performance in ideal conditions. Of course, in the real world, security applications very rarely deliver anything close to ideal conditions.
Hard drives are complex devices and by the very nature of their design can be fragile. The next phases of testing are designed to put Seagate’s claims of enhanced reliability and performance to the test.
A final rating for the Seagate Skyhawk 10TB surveillance HDD will not be issued until all elements of the long-term test have been completed. At present, all we can say is that under normal conditions the drives deliver what the manufacturer has promised.
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