Dell DC, 3, User Manual

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94 Configuring PERC 3
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Maximizing Capacity
RAID 0 achieves maximum drive capacity, but does not provide data
redundancy. Maximum drive capacity for each RAID level is shown below.
original equipment manufacturer (OEM) level firmware that can span up to
four logical drives is assumed. Table 7-7 displays the drives required, and
capacity for the various RAID levels.
Maximizing Drive Availability
You can maximize the availability of data on the physical disk drive in the
logical array by maximizing the level of fault tolerance. The levels of fault
tolerance provided by the RAID levels are shown in Table 7-8.
Ta b l e 7 - 7 . D r i v e s a n d C a p a c i t i e s f o r E a c h R A I D L e v e l
RAID
Level Description Drives
Required Capacity
0 Striping without
parity
1 – 32 (Number of disks) X (capacity of
smallest disk)
1 Mirroring 2 (Capacity of smallest disk) X (1)
5 Striping with
floating parity
drive
3 – 32 (Number of disks) X (capacity of
smallest disk) - (capacity of 1
disk)
10 RAID 1 and
striping
4 – 16
(Must be a
multiple of
2)
(Number of disks) X (capacity of
smallest disk) / (2)
50 RAID 5 and
striping
6 – 256
(Must be a
multiple of
arrays)
(Number of disks) X (capacity of
smallest disk) – (capacity of 1
disk X number of arrays)
Ta b l e 7 - 8 . Fa u l t To l e r a n c e Fe a t u r e s f o r R A I D L e v e l s 0 , 1
a n d 5
RAID
Level Fault Tolerance Protection
0 No fault tolerance
1 Disk mirroring, which provides 100% data redundancy.