Comparison of AV and Surveillance Class Hard Drives

surveillance class hard drives

Not All Hard Drives are created equal.

There are a great deal of technical and usage case factors that go into choosing the right hard drives for your specific requirements. This is a short introduction to some of the differences between two classes of hard Drives:While a surveillance hard drive forms a central component to the digital storage of surveillance video. It can be used in a DVR, NVR, Video Server or a Video Management System in order to work 24 hours a day and 7 days week. These hard drives need to be always active, in order to keep video evidence live.

A surveillance system can be write intensive, writing data up to 90% of the time. To support such a workload, ImagePerfect is tuned for multiple seamless video recording environments with the highest throughput performance. Besides helping to ensure the highest level of video integrity during recording, ImagePerfect also enables real-time big data analytics.

Choose the correct hard drive for your application.

Drive Class: AV / Surveillance

Hard drive manufacturers design drives that will perform well for their largest customers, or sets of customers. This is why “classes” of drives exist.

Design Expectations:

The information below is a high-level set of expectations the drive manufacturers have when designing, testing and selling “AV / Surveillance” (AV is synonymous with Consumer Audio/Video) drives.

 

HARD DRIVE CLASS:SurveillanceConsumer Audio/Video
POWER ON HOURS24 hrs/7 days (8760 POH)24 hrs/7 days (8760 POH)
WRITE / READ RATIO90/1060/40
BLOCK SIZESLargeLarge
SEEK PROFILE5% Random / 95% Sequential10% Random / 90% Sequential

Design Details:

“AV” (also called “Video”) drives are tuned to recognize and manage “streams” of data (AV steams), and using firmware-based features, they can keep themselves ahead of the host’s needs, and perform specific housekeeping and protective tasks that neutralize the issues caused by this specific, highly repetitive use case. The AV drive is tuned around 5 to 7 streams of data, with intermittent OS updates and logging activities.

“Surveillance” drives evolved from, and are closely related to, AV drives, but are tuned for the higher number of data streams used in commercial and industrial video security applications. There are some proprietary uniqueness in the stream recognition and cache management strategies of Surveillance drives. These special drive families are dedicated to the needs of the video security industry, which means that they will evolve as the industry’s needs evolve. These are called Surveillance class hard drives and are the hard drives that ensure video surveillance systems function.

The table below is an excerpt from the HDSTOR Drive Comparison Table, which shows features (or lack thereof) of the different classes of drives, as well as relative performance, reliability and cost comparing Surveillance class hard drives and AV class hard drives.

 

HARD DRIVE CLASS:SurveillanceConsumer Audio/Video
PRODUCTION SCREENING?YESYES
RATED FOR 24/7 USE?
YESYES
FIXED SHAFT SPINDLE?SOME
NO
RV FEED FORWARD SENSORS?
SOME
NO
TIME LIMITED RETRY TABLES?YESYES
WORKLOAD RATING
MEDIUMMEDIUM
FIRMWARE TUNINGVolume Streaming DataBedroom Quiet/ Low Power
PERFORMANCE CAPABILITIES
MEDIUMMEDIUM
RELIABILITY RATINGSMEDIUMMEDIUM
COSTMEDIUMMEDIUM

 

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