Chapter 10. Best Practices For Rxt Media; Raid Overview - Spectra Logic T-Series Spectra T950 User Manual

10 Best Practices for RXT Media
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 Overview

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.
RXT RAID Level Options
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.
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