Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 20)

Chapter 1. Introduction to the 3ware Command Line Interface
12 3ware SATA+SAS RAID Controller Card CLI Guide, Version 10.2
technology, read performance during a sequential read operation is twice the
speed of a single drive.
The adaptive algorithms in TwinStor technology boost performance by
distinguishing between random read request and sequential read requests. For
the sequential read requests generated when accessing large files, both drives
are used with the drive heads simultaneously reading alternating sections of
the file. For the smaller random transactions, the data is read by a single
optimal drive head.
Figure 2. RAID 1 Configuration Example
RAID 5
RAID 5 provides performance, fault tolerance, high capacity, and storage
efficiency. It requires a minimum of three drives and combines striping data
with parity (exclusive OR) to restore data in case of a drive failure.
Performance and efficiency increase as the number of drives in a unit
increases.
Parity information is distributed across all of the drives in a unit rather than
being concentrated on a single disk (see Figure 3). This method avoids
throughput loss due to contention for the parity drive.
RAID 5 can tolerate one drive failure in the unit.
Figure 3. RAID 5 Configuration Example
(480 GB - 120 GB for parity)