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Chapter 2. RAID Array Controller
EK–SMCPQ–UG. C01 2–9
There are some restrictions you must adhere to when creating a RAID set using
the RAID 3000 shelf. The minimum and maximum number of drives required to
support each RAID level is listed in Table 2–3.
Table 2–3 Shelf RAID Set Restrictions
RAID Level Min. No. of
Drives
Max. No. of
Drives
JBOD 1 1
02 24
12 24
0+1* 4 16
43 24
53 24
*
Must be even number.
2.6.1 RAID 0
RAID 0 breaks up data into smaller chunks and writes each chunk to a different
drive in the array. The size of each chunk is determined by the controller’s chunk
size parameter, which you set in the course of creating a RAID set.
The advantage of RAID 0 is its high bandwidth. By breaking up a large block of
data into smaller chunks, the controller can use multiple drive channels to write
the chunks to the disk drives. Furthermore, RAID 0 involves no parity calcula-
tions to complicate the write operation. Likewise, a RAID 0 read operation em-
ploys multiple drives to assemble a single, large data block. This makes RAID 0
ideal for applications such as graphics, video, and imaging that involve the writ-
ing and reading of large, sequential blocks. Figure 2–5 shows a diagram of a
RAID 0 write.
CAUTION
The lack of parity means that a RAID 0-disk array
offers no redundancy and thus cannot recover
from a drive failure.