Avago Technologies MegaRAID Fast Path Software - Manual (Page 33)

LSI Corporation Confidential | July 2011 Page 33
MegaRAID SAS Software User Guide Chapter 2: Introduction to RAID | RAID Levels
RAID 60, a combination of RAID 0 and RAID 6, uses distributed parity, with two
independent parity blocks per stripe in each RAID set, and disk striping. A RAID 60
virtual drive can survive the loss of two drives in each of the RAID 6 sets without losing
data. RAID 60 works best with data that requires high reliability, high request rates, high
data transfers, and medium-to-large capacity.
2.5.2 Selecting a RAID Level To ensure the best performance, you should select the optimal RAID level when you
create a system drive. The optimal RAID level for your drive group depends on a
number of factors:
 The number of drives in the drive group
 The capacity of the drives in the drive group
 The need for data redundancy
 The disk performance requirements
2.5.3 RAID 0 RAID 0 provides disk striping across all drives in the RAID drive group. RAID 0 does not
provide any data redundancy, but RAID 0offers the best performance of any RAID level.
RAID 0 breaks up data into smaller segments, and then stripes the data segments
across each drive in the drive group. The size of each data segment is determined by
the stripe size. RAID 0 offers high bandwidth.
NOTE: RAID level 0 is not fault tolerant. If a drive in a RAID 0 drive group fails, the entire
virtual drive (all drives associated with the virtual drive) fails.
By breaking up a large file into smaller segments, the RAID controller can use both SAS
drives and SATA drives to read or write the file faster. RAID 0 involves no parity
calculations to complicate the write operation. This situation makes RAID 0 ideal for
applications that require high bandwidth but do not require fault tolerance.
Table 7
provides an overview of RAID 0. Figure 7 provides a graphic example of a RAID 0 drive
group.
Table 7: RAID 0 Overview
Uses Provides high data throughput, especially for large files. Any environment
that does not require fault tolerance.
Strong points Provides increased data throughput for large files.
No capacity loss penalty for parity.
Weak points Does not provide fault tolerance or high bandwidth.
All data is lost if any drive fails.
Drives 1 to 32