Dahua DH-XVR42 AN-I Series User Manual page 304

Select group for each HDD, and then click Apply to complete the settings.
Step 2
After configuring HDD group, click Main Stream, Sub Stream and Snapshot tabs
Step 3
respectively, to configure the saving of main stream, sub stream and snapshot information
of different channels to different HDD groups.
Figure 5-258 Disk group
Figure 5-259 Main stream
288
User's Manual