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Chapter 7:
Technology Background
209
Chapter 7: Technology Background
7.1 Introduction to RAID
RAID (Redundant Array of Independent Disks) allows multiple disk drives to be
combined together into a RAID Volume. You create a RAID Volume on your
SmartStor when you perform the setup procedure, either in SmartNAVI or the
WebPASM Setup Wizard.
The benefits of a RAID can include:
․
Higher data transfer rates for increased server performance
․
Increased overall storage capacity for a single Volume
․
Data redundancy/fault tolerance for ensuring continuous system operation in
the event of a disk drive failure
Different RAID levels use different organizational models and have varying
benefits. Also see “Choosing a RAID Level” on page 212. The following outline
breaks down the properties for each RAID level supported on the SmartStor:
Note: 2 Bay NAS only supports RIAD 0, 1.
RAID 0 - Stripe
When a RAID Volume is striped, the read and write blocks of data are
interleaved between the sectors of multiple disk drives. Performance is
increased, since the workload is balanced between drives or “members” that
form the RAID Volume.
Identical drives are recommended for performance as well as data storage
efficiency.
Figure 1. RAID 0 Striping interleaves data across multiple drives
The RAID Volume’s data capacity equals the capacity of the smallest disk drive
times the number of disk drives. For example, one 100 GB and three 120 GB
drives will form a 400 GB (4 x 100 GB) RAID Volume instead of 460 GB.
If disk drives of different capacities are used, there will also be unused capacity
on the larger drives.
Because RAID 0 does not offer Fault Tolerance, meaning that you cannot
recover your data after a disk drive failure, Promise does not recommend a
Data Stripe
Disk drives