Disk subsystem requirements

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General information

This section provides the requirements for the performance (IOPS) and disk subsystem capacity for the correct operation of Axxon One.

Performance requirements (IOPS)

The performance of the disk subsystem is measured in input/output operations per second (IOPS). The disk (or array) must provide an IOPS value no lower than the estimated value, determined by the software load.

Features of working with an archive

Axxon One interacts with the archive in fixed-size blocks:

Write: Data is written in blocks of 4 MB (for block storage) or 64 MB (for object storage). Block generation takes no more than 10 seconds (for block storage) or no more than 60 seconds (for object storage). If a block isn't completely filled within this interval, a fragment is written to disk. This fragment will be added to later (see Аrchive).
Read: Archive playback (viewing) is also performed in blocks. The exception is the reindexing process (see Console utility for working with archives (vfs_format.exe)).

IOPS calculation

Below are the formulas for calculating IOPS depending on the usage case and the average bitrate of the cameras.

Attention!

The 3.6 Mbps limit is approximate. When calculating, keep in mind that when writing an archive, both write (input) and read (output) operations are performed simultaneously, which are necessary for service purposes.

Camera average bitrate	Write IOPS	Read IOPS
Archive recording only
Less than ~3.6 Mbps	0.29 × N	0.035 × M
More than ~3.6 Mbps	0.065 × M	0.035 × M
Archive playback only
When viewing, only read operations are performed	0.035 × R × S
Simultaneous recording and viewing of the archive
Less than ~3.6 Mbps	0.29 × N	0.035 × M + 0.035 × R × S
More than ~3.6 Mbps	0.065 × M	0.035 × M + 0.035 × R × S
Names of variables N is the number of cameras recording to the archive. M is the total bitrate (Mbps) of all cameras participating in the recording. R is the total bitrate (Mbps) of cameras played back from the archive (at 1x speed). S is the playback speed (for example, 2.0 for fast playback).

Recommendations for disk arrays (RAID)

When you use RAID controllers, you must set the cache policy to Write-Back to ensure maximum write performance.

Requirements for disk subsystem capacity

The total disk space consists of the capacity required to store video data (archive), system log, metadata, and service information.

Minimum installation requirements

To install the Axxon One distribution package, you need:

Windows OS: at least 20 GB of free disk space.
Linux OS: at least 10 GB of free disk space.

Attention!

The specified values don't include the space for the video archive (see Аrchive), metadata database (see Metadata database), system log (see System log), and DetectorPack add-on (see Installing DetectorPack add-ons). The calculations for them are provided below.

Calculation for video server (archive) capacity

The estimated disk space required to store a video archive can be determined using the following formula:

Capacity (MB) = Storage T x N cameras x Bitrate x 450 x Recording T

Names of variables

Storage T is the required time of archive storage (in days).
N cameras is the number of cameras recording.
Bitrate is the average bitrate of one camera (in Mbps).
450 is the conversion factor from Mbps to MB/h ((60 × 60) / 8).
Recording T is the number of hours of recording of one camera per day (hours/day). If recording is 24 hours a day, the value is 24.

The average bitrate

The average bitrate depends on the codec, camera manufacturer, compression settings, scene dynamics, resolution, and hardware settings (see Platform Calculator). Examples for 1920x1080 resolution:

Video codec	Bitrate
H.264	4 Mbps
H.265	2.6 Mbps

Example of calculation (without the log database and metadata database) for 1920×1080 resolution

Recording parameters	Calculation results (total capacity)
4 cameras, 25 FPS, 1920×1080, 24/7 recording, 7-day storage	H.264: ~1,15 TB H.265: ~0,75 TB

Calculation for the system log database

The size of the system log database depends on the number of configured detectors and their activity.

Detector activity	Сalculation formula
Low	D × T × 0.04 GB
Medium	D × T × 0.12 GB
High	D × T × 0.48 GB
Names of variables D is the total number of detectors in the system. T is the storage period (days) of the system log.

Calculation for the metadata database

We recommend calculating the size for the metadata database using one of the formulas, depending on the need to reserve space.

Size	Сalculation formula
Sufficient	N × T × 0.5 GB
With margin	N × T × 1 GB
With a large margin	N × T × 5 GB
Names of variables N is the number of detectors with enabled metadata recording (multiple detectors can be enabled for a single camera; see Metadata database). T is the period (days) of metadata storage. The default value is 30 days. Attention! If free disk space drops to 15 GB, the overwriting mechanism automatically starts: new data is written over the oldest data.

Additional requirements

When you plan disk space, consider the following:

System logs: We recommend allocating at least 1 GB for the system log archive.
Self-diagnostics service: Service data can take up to 100 MB per day. The storage depth of the internal service database is limited to 7 days or 512 MB (whichever is reached first).

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