1. Single mode

　Images and audio from the cameras will be recorded on each HDD in order.

2. Mirroring mode (V2.0 or later)

　The same images and audio from the cameras will be recorded on 2 HDDs like HDD1 and HDD2, HDD3 and HDD4.
　When one of the two HDDs is replaced with a new one, it is possible to copy data (Mirroring recovery) on the other HDD to the replaced HDD.This product or the extension unit requires 2 or more HDDs.

3. RAID5 mode

　Image and audio is recorded across all HDDs.
　1 parity HDD is used for fault tolerance, so the usable storage is reduced by 1 x HDD.
　Even if one of the HDDs becomes faulty, recorded images can be recovered using the other remaining HDDs.
　This product or the extension unit requires three or more HDDs.

4. RAID6 mode

　Image and audio is recorded across all HDDs.
　2 parity HDDs are used for fault tolerance, so the usable storage is reduced by 2 x HDDs.
　Even if 2 of the HDDs become faulty, recorded images can be recovered using the other remaining HDDs. This product or the extension unit requires four or more HDDs.