Руководство Пользователя для Spectra Logic spectra t120

103

The information provided in this chapter is integral to understanding all aspects of 
media handling and inventory management. It includes very helpful information on:

• RAID Overview on page 103

• Optimizing Performance on page 104

• Maintaining RXT Drives and Media Packs on page 105

• Using in Daily Operation on page 106

RAID stands for Redundant Array of Independent Disks. It is a system of using 
multiple hard drives for sharing or replicating data. RAID is not a replacement for a 
good backup system and policy; rather, it should be seen as added insurance against 
data loss and business disruption.

There are multiple RAID levels, each one providing different levels of performance and 
protection. RXT is available in four RAID configurations: 

• RAID 0 provides the best read/write performance and takes full advantage of 

available capacity, but provides no redundancy. Data is split up across the drives 
(called striping) to maximize throughput. However, if a disk fails, your data is 
unrecoverable. 

• RAID 1 offers moderate performance and full redundancy. Data is mirrored to—that 

is, exact copies are written to—two different disks. If one disk fails, the remaining 
one has a complete version of your data, and that data can be replicated once the 
bad drive is replaced. However, this option halves available disk capacity. For 
example, 1 TB of raw disk provides 500 GB of usable capacity in a RAID 1 
configuration.

• RAID 5 provides good performance with a reasonable amount of data protection. 

Data is striped across multiple drives, and error correction information—parity—
distributed among the drives. If one disk drive fails, the parity information from the 
remaining disks can be used to rebuild your data. The penalty of redundancy in this 
configuration is that parity consumes approximately 20% of your total disk capacity.