Understanding RAID Concepts and Levels
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11
Available RAID Configurations
The following RAID levels and configurations are available for drives
attached to a 3ware controller:
RAID 0
RAID 1
RAID 5
RAID 10
RAID 50
Single Disk
JBOD
Hot Spare
RAID 0
Provides striping, but no mirroring. Striped disk arrays achieve high transfer
rates because they can read and write data on more than one drive
simultaneously. The stripe size is configurable in the 3ware CLI, 3ware BIOS
Manager (3BM) and in the 3ware Disk Manager (3DM 2). Requires a
minimum of two drives.
When drives are configured in a striped disk array (see Figure 1), large files
are distributed across the multiple disks using RAID 0 techniques.
Striped disk arrays give exceptional performance, particularly for data
intensive applications such as video editing, computer aided design and
geographical information systems.
RAID 0 arrays are not fault tolerant. The loss of any drive results in the loss of
all the data in that array, and can even cause a system hang, depending on
your operating system. RAID 0 arrays are not recommended for high
availability systems unless additional precautions are taken to prevent system
hangs and data loss.
Figure 1. RAID 0 Configuration Example
RAID 1
Also known as a mirrored array. Mirroring is done on pairs of drives.
Mirrored disk arrays write data to two drives using RAID 1 algorithms (see