166
Promise
Technology
Pegasus3 R4/R6/R8
Recommended Applications for RAID 1E:
•
Imaging applications
•
Database servers
• General fileserver
RAID 5 – Block and Parity Stripe
RAID 5 organizes block data and parity data across the physical drives. Generally, RAID Level 5 tends
to exhibit lower random write performance due to the heavy workload of parity recalculation for each
I/O. RAID 5 is generally considered to be the most versatile RAID level. It works well for file, database,
application and web servers.
RAID 5 stripes all drives with data and parity information
The capacity of a RAID 5 logical drive equals the smallest physical drive times the number of physical
drives, minus one. Hence, a RAID 5 logical drive with four 100 GB physical drives has a capacity of
300 GB. A RAID 5 logical drive with two 120 GB physical drives and one 100 GB physical drive has a
capacity of 200 GB. RAID 5 is generally considered to be the most versatile RAID level.
Advantages
Disadvantages
•
Implemented as a mirrored disk array whose
segments are RAID 0 disk arrays
•
High I/O rates are achieved thanks to
multiple stripe segments
•
Can use an odd number of disks
•
Very high disk overhead – uses only 50% of
total capacity
Distributed Parity
Data
Blocks
Physical Drives
Summary of Contents for Pegasus3 R4
Page 4: ...iv Promise Technology Pegasus3 R4 R6 R8 VCCI KCC FCC ...
Page 5: ...v About this guide Pegasus3 Product Manual WARNING WARNING WARNING WARNING ...
Page 80: ...67 Managing the Pegasus3 Pegasus3 Product Manual Controller Settings ...
Page 207: ...194 Promise Technology Pegasus3 R4 R6 R8 View NVRAM Events ...