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Chapter 1. Introduction to the 3ware Command Line Interface
Figure 2). This gives your system fault tolerance by preserving the data on
one drive if the other drive fails. Fault tolerance is a basic requirement for
mission critical systems like web and database servers.
3ware uses a patented technology, TwinStor®, on RAID 1 arrays for
improved performance during sequential read operations. With TwinStor
technology, read performance is twice the speed of a single drive during
sequential read operation.
The adaptive algorithms in TwinStor technology boost performance by
distinguishing between random and sequential read requests. For the
sequential requests generated when accessing large files, both drives are used,
with the heads simultaneously reading alternating sections of the file. For the
smaller random transactions, the data is read from a single optimal drive head.
Figure 2. RAID 1 Configuration Example
RAID 5
Combines striping data with parity (exclusive OR) to restore data in case of a
drive failure. This array type provides performance, fault tolerance, high
capacity, and storage efficiency. Requires a minimum of three drives.
Parity information is distributed across all drives rather than being
concentrated on a single disk (see Figure 3). This avoids throughput loss due
to contention for the parity drive.
Figure 3. RAID 5 Configuration Example
RAID 10
This array is a combination of RAID 1 with RAID 0. Striped and mirrored
arrays for fault tolerance and high performance. Requires a minimum of four
drives to use both RAID 0 and RAID 1 techniques.
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RAID 5
0 parity
B0
C0
A1
1 parity
C1
A2
B2
2 parity
A3
B3
C3
A4
B4
C4
A Blocks
B Blocks
C Blocks
3ware 9000 Series Serial ATA Controller CLI Guide
E0
D0
E1
D1
E2
D2
E3
3 parity
4 parity
D4
E Blocks
D Blocks
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