The value set in the CMX Circular Record option is the amount of hdd space CMX will not use on the destination HDD.
(This value can be set independently per destination HDD within the CMX System Settings)
In the example above the Circular Record value is set to 6GB. This means CMX will leave 6GB of HDD space on the selected D: before recycling its recording through the HDD.
So as an example, if you have a 2TB HDD and you only want to assign half of it for CCTV recordings, rather than partition the disk in 2 halves you can simply set the CMX Circular Record value to 1000GB. This will only allow CMX to use approximately half of your HDD. This value can be adjusted at any point.
We do not recommend changing the selected value to a lower number than the original default value. Windows requires a certain amount of free HDD space for hidden system and temporary files, setting this value to low may result in Windows OS problems or other issues.