User`s guide
Appendix B: Understanding RAID ● 74
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. 
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.
RAID level Redundancy
Disk Drive 
Usage
Read 
Performance
Write 
Performance
Built-in Hot 
Spare
Minimum
Disk Drives
RAID 0 No 100%
 
No 2
RAID 1 Yes 50%
 
No 2
RAID 1E Yes 50%
 
No 3
RAID 10 Yes 50%
 
No 4
RAID 5 Yes 67 – 94%
 
No 3
RAID 5EE Yes 50 – 88%
 
Yes 4
RAID 50
1
1
Because it supports a maximum of four disk drives, the Adaptec 2420SA RAID controller can’t support RAID 50 or RAID 60. 
Yes 67 – 94%
 
No 6
RAID 6 Yes 50 – 88%
 
No 4
RAID 60
*
Yes 50 – 88%
 
No 8










