Raid 0; Raid 1 - Lenovo ThinkServer RD330 Software User's Manual

MegaRAID SAS Software User Guide
2.5.3

RAID 0

2.5.4

RAID 1

RAID 0 provides disk striping across all drives in the RAID drive group. RAID 0 does not
provide any data redundancy, but, along with RAID 0, does offer 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 whole
virtual drive (all drives associated with the virtual drive) will fail.
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 makes RAID 0 ideal for applications
that require high bandwidth but do not require fault tolerance.
overview of RAID 0. Figure 7
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 lost if any drive fails.
Drives 1 to 32
Segment 1 Segment 2
Segment 3 Segment 4
Segment 5 Segment 6
Segment 7 Segment 8
Figure 7: RAID 0 Drive Group Example with Two Drives
In RAID 1, the RAID controller duplicates all data from one drive to a second drive in the
drive group. RAID 1 supports an even number of drives from 2 through 32 in a single
span. RAID 1 provides complete data redundancy, but at the cost of doubling the
required data storage capacity.
provides a graphic example of a RAID 1 drive group.
Table 8: RAID 1 Overview
Uses Use RAID 1 for small databases or any other environment that requires fault
tolerance but small capacity.
provides a graphic example of a RAID 0 drive group.
Table 8 provides an overview of RAID 1.
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Chapter 2: Introduction to RAID RAID Levels
Table 7 provides an
Figure 8
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