What Is CMR and Why Does It Matter for AI Surveillance?
Conventional Magnetic Recording, or CMR, writes data to distinct magnetic tracks on the disk. This recording method is commonly used in drives intended for sustained workloads, predictable write behavior, and multi-drive environments. The Toshiba S300 AI HDD uses CMR across all available capacities.
How CMR Stores Data
CMR tracks are written without intentionally overlapping adjacent tracks. This allows data to be rewritten without reorganizing neighboring tracks, supporting predictable performance during sustained write activity.
Why Surveillance Workloads Matter
Video surveillance systems may write multiple streams continuously. AI-enabled systems can add metadata and random-write activity. A drive designed with CMR and surveillance-optimized firmware can support these combined workloads.
CMR and Multi-Bay Systems
Multi-bay NVRs and analytics servers may require consistent performance across several drives. Recording technology is one factor, along with rotational-vibration sensors, workload rating, cache, and host compatibility.
S300 AI Recording Technology
The S300 AI uses CMR, operates at 7200 RPM and includes up to 1GB of cache. It is designed to support up to 64 camera streams, up to 32 AI streams and workload rate up to 550TB per year.
Selecting a Drive
Recording technology should be reviewed together with capacity, workload rate, supported drive bays, operating requirements, and compatibility. No single specification should be used by itself to select a surveillance drive.
Product Recommendation
For AI-enabled surveillance, choose a drive designed for multi-stream recording and analytics workloads rather than selecting only by capacity.
Frequently Asked Questions
What does CMR mean?
Does the Toshiba S300 AI use CMR?
Is CMR the only factor in surveillance HDD selection?
1 One Terabyte (1 TB) means 1012 = 1,000,000,000,000 bytes using powers of 10. A computer operating system, however, reports storage capacity using powers of 2 for the definition of 1 TB = 240 = 1,099,511,627,776 bytes, and therefore shows less storage capacity. Available storage capacity (including examples of various media files) will vary based on file size, formatting, settings, software and operating system and other factors. Actual formatted capacity may vary.
2 Compatibility may vary depending on user's hardware configuration, and operating system.
3 Product specifications, configurations, components, and features are subject to change without notice.
4 Annual Workload Rating: HDDs keep track of various drive usage such as power on hours, lifetime writes and lifetime reads from the host computer. With this data we calculate an Annualized Workload Rate, under 40 deg. C ambient environments, Annualized Workload Rate = (Lifetime Writes + Lifetime Reads) * (8760 / Lifetime Power On Hours) in case Power On time is 8760h or longer. Otherwise (i.e. Power On time is shorter than 8760h), Annualized Workload Rate = (Lifetime Writes + Lifetime Reads) Each drive is designed to perform up to the Annualized Workload Rate stated, after which the drive may be expected to decline. The Annualized Workload Rate in no way alters the warranty policy for such drive. Workload is defined as the amount of data written, read or verified by commands from host system.
5 Number of surveillance cameras support capability is defined by performance simulation with High Definition cameras at up to 10 Mbps rate, depending on the HDD model. Actual results may vary based on various factors, including the types of cameras installed, the system’s hardware and software capabilities, and the video compression technology used, as well as system variables such as resolution, frames per second, and other settings. Compatibility may vary depending on user’s hardware configuration and operating system. “High Definition” is calculated assuming Full HD 1080p, 30fps, transfer rate of up to 10Mbps/stream.
6 For "Drive Bays Supported", please contact your Solutions Provider because the compatibility with the host device will vary based on the system.
7 MTTF (Mean Time to Failure) or MTBF (Mean Time Between Failure) is not a guarantee or estimate of product life; it is a statistical value related to mean failure rates for a large number of products which may not accurately reflect actual operation. Actual operating life of the product may be different from the MTTF or MTBF. MTTF (Mean Time to Failure) or MTBF (Mean Time Between Failure) of the HDDs during its life time is 600,000 hours and AFR(Annualized Failure Rate) is 1.46%, or 1.0 million hours and AFR is 0.88%, or 1.2 million hours and AFR is 0.73%, or 2.5 million hours and AFR is 0.35% (depending on HDD models). This assumes power-on hours are 24 x 7 in normal usage (8760 h/year power on hours, up to 180 TB/year, or up to 300TB/year, or up to 550 TB/year total data transfers (depending on HDD models), and average HDA surface temperature:40°C or less). Use at case HDA surface temperature above 40°C may degrade product reliability and reduce warranty period.
8 Drive life may vary depending on usage and workload. See also MTTF and Annual Workload Rating for more details.
9 CMR is Conventional Magnetic Recording technology.
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