Selecting The Best Raid Level - Adaptec SCSI 58300 Installation And User Manual

Drive segment size is limited to the size of the smallest disk drive in the array. For instance, an
array with two 250 GB disk drives and two 400 GB disk drives can create two mirrored drive
segments of 250 GB, for a total of 500 GB for the array, as shown in the following figure.
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
Disk Drives in Logical Drive

Selecting the Best RAID Level

Use this table to select the RAID levels that are most appropriate for the logical drives on your
storage space, based on the number of available disk drives and your requirements for
performance and reliability.
RAID
Level Redundancy
RAID 0 No
RAID 1 Yes
RAID Yes
10
Disk drive usage, read performance, and write performance depend on the number of drives in
the logical drive. In general, the more drives, the better the performance.
Drive Segment Size (Smallest Disk Drive)
250 GB
250 GB
Disk Drive 1
Disk Drive 2
400 GB
Disk Drive 3
Disk Drive 4
400 GB
RAID 10 Logical Drive = 500 GB
Disk Drive Read
Usage Performance
100% www
50% ww
50% ww
Appendix B: Understanding RAID
1 499
3 ...
2 500
4 ...
1 499
3 ...
Unused Space: 150 GB
Not Used
2 500
4 ...
Unused Space: 150 GB
Not Used
Write Built-in
Performance Hot Spare
www No
ww No
ww No
66
●
Minimum
Disk
Drives
2
2
4