Raid 50 - Lenovo ThinkServer RD650 User Manual

12Gb/s MegaRAID SAS Software User Guide
March 2014
Table 12 RAID 10 Overview
Uses
Strong Points
Weak Points
Drives
In the following figure, virtual drive 0 is created by distributing data across four drive groups (drive groups 0 through
3).
Figure 12 RAID 10 Level Virtual Drive
2.2.9

RAID 50

RAID 50 provides the features of both RAID 0 and RAID 5. RAID 50 includes both distributed parity and drive striping
across multiple drive groups. RAID 50 is best implemented on two RAID 5 drive groups with data striped across both
drive groups.
RAID 50 breaks up data into smaller blocks and then stripes the blocks of data to each RAID 5 disk set. RAID 5 breaks
up data into smaller blocks, calculates parity by performing an exclusive OR operation on the blocks, and then writes
the blocks of data and parity to each drive in the drive group. The size of each block is determined by the stripe size
parameter, which is set during the creation of the RAID set.
RAID level 50 can support up to eight spans and tolerate up to eight drive failures, though less than total drive
capacity is available. Though multiple drive failures can be tolerated, only one drive failure can be tolerated in each
RAID 5 level drive group.
The following table provides an overview of RAID 50.
Appropriate when used with data storage that needs 100 percent redundancy of mirrored drive groups and
that also needs the enhanced I/O performance of RAID 0 (striped drive groups.) RAID 10 works well for
medium-sized databases or any environment that requires a higher degree of fault tolerance and
moderate-to-medium capacity.
Provides both high data transfer rates and complete data redundancy.
Requires twice as many drives as all other RAID levels except RAID 1.
4 to 32 in multiples of 4 — The maximum number of drives supported by the controller (using an even number
of drives in each RAID 10 virtual drive in the span).
LSI Corporation
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Chapter 2: Introduction to RAID
RAID Levels