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B840MT-E | A620MS-E
4.2 RAID Functions
RAID Definitions
In a RAID 0 system data are split up in blocks that get
written across all the drives in the array. By using multiple
disks (at least 2) at the same time, this offers superior I/O
performance. This performance can be enhanced further by
using multiple controllers, ideally one controller per disk.
Features and Benefits
• Drives: Minimum 2, and maximum is up to 6 or 8. Depending on the platform.
• Uses: Intended for non-critical data requiring high data throughput, or any environment
that does not require fault tolerance.
• Benefits: provides increased data throughput, especially for large files. No capacity loss
penalty for parity.
• Drawbacks: Does not deliver any fault tolerance. If any drive in the array fails, all data is
lost.
• Fault Tolerance: No.
• Total Capacity: (Minimal. HDD Capacity) x (Connected HDDs Amount)
Data are stored twice by writing them to both the data disk
(or set of data disks) and a mirror disk (or set of disks) . If
a disk fails, the controller uses either the data drive or the
mirror drive for data recovery and continues operation. You
need at least 2 disks for a RAID 1 array.
Features and Benefits
• Drives: Minimum 2, and maximum is 2.
• Uses: RAID 1 is ideal for small databases or any other application that requires fault
tolerance and minimal capacity.
• Benefits: Provides 100% data redundancy. Should one drive fail, the controller switches
to the other drive.
• Drawbacks: Requires 2 drives for the storage space of one drive. Performance is impaired
during drive rebuilds.
• Fault Tolerance: Yes.
Chapter 4: Useful help | 37