What hard drives are compatible with the GVR3550?

The GVR3550 is designed to recording video with highest priority. When the CPU usage is high, the GVR3550 will reduce the channels of local view automatically to guarantee the recording performance.
Advised that no more than 16 channels of simultaneously recording when using RAID 1. For 24 channel recording, because of the very high CPU usage, advised to reduce to use 2nd stream local view (VGA or HDMI),
or close the local view to save resource.

The rule of thumb is any 3.5 inch  SATA (revision II or III; or 3.0Gb/s  above interface) HDD with spin speed more than 7200rpm should do the job. Of course if resource permitted, same interface standard SSD is the best choice.

GVR3550 HDD Compatibility list