Dell 3 - Manual (Page 100)

98 Configuring PERC 3
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Using the Array Configuration Planner
Table 7-12 lists RAID levels, fault tolerance, and effective capacity for some
possible drive configurations for an array consisting of one to 32 drives. This
table does not take into account any hot spare (standby) drives. You should
always have a hot spare drive in case of drive failure. RAID 1 requires two
drives. RAID 5 requires at least three drives. RAID 10 requires at least four
drives. RAID 50 requires at least six drives.
Ta b l e 7 - 1 2 . A r r a y C o n f i g u r a t i o n P l a n n e r
Number
of Drives Possible RAID
Levels Relative
Performance Fault
Tolerance Effective
Capacity
1 RAID 0 Excellent No 100%
2 RAID 0 Excellent No 100%
2 RAID 1 Good Yes 50%
3 RAID 0 Excellent No 100%
3 RAID 5 Good Yes 67%
4 RAID 0 Excellent No 100%
4 RAID 5 Good Yes 75%
4 RAID 10 Good Yes 50%
5 RAID 0 Excellent No 100%
5 RAID 5 Good Yes 80%
6 RAID 0 Excellent No 100%
6 RAID 5 Good Yes 83%
6 RAID 10
(spanned)
Excellent Yes 50%
6 RAID 50
(spanned)
Good Yes 67%
7 RAID 0 Excellent No 100%
7 RAID 5 Good Yes 86%
8 RAID 0 Excellent No 100%
8 RAID 5 Good Yes 87%
8 RAID 10
(spanned)
Excellent Yes 50%