Filer Disks

Data disks
Spare disks
Parity disks
Double parity disks
Broken and failed disks

Maximum number of RAID groups in an aggregate : 150

Maximum number of RAID groups on a storage system : 400

These are type of disks in filler

Data ONTAP 8.0.1 Default and Maximum RAID Group Size by Drive Type
Drive Type	RAID Type	Default RAID Group Size	Maximum RAID Group Size
SSD	RAID-DP (default)	23 (21+2)	28 (26+2)
	RAID 4	8 (7+1)	14 (13+1)
SAS/FC	RAID-DP (default)	16 (14+2)	28 (26+2)
	RAID 4	8 (7+1)	14 (13+1)
SATA	RAID-DP (default)	14 (12+2)	20 (18+2)
	RAID 4	7 (6+1)	7 (6+1)