Seagate 8TB internal hard drive with SATA interface.

AV and Surveillance

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.
Power On Hours 24 hrs/7 days (8760 POH) 24 hrs/7 days (8760 POH)
Write / Read Ratio 90/10 60/40
Block Sizes Large Large
Seek Profile 5% Random / 95% Sequential 10% 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.

Comparison Table

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.
Production Screening? YES YES
Rated for 24/7 Use? YES YES
Fixed Shaft Spindle? SOME NO
RV Feed Forward Sensors? SOME NO
Time Limited Retry Tables? YES YES
Workload Rating MEDIUM MEDIUM
Firmware Tuning Volume Streaming Data Bedroom Quiet/ Low Power
Performance Capabilities MEDIUM MEDIUM
Reliability Ratings MEDIUM MEDIUM
Cost MEDIUM MEDIUM