Gateway E-842R, User Manual

Page: 52 / 164

CHAPTER 4: Configuring your storage solution www.gateway.com
46
Optimization and drive selection for RAID 5 arrays
Typical RAID 5 implementations require a number of steps to write the data to
the drives. In order to optimize your system performance based on the type of
writes you expect in your operation, we have provided detailed information on
optimizing the performance using full strip write operations in an appendix. If
you intend to setup a RAID 5 array and want to consider optimum performance,
you need to consider the number of data drives, parity drives, and chunk size.
For a review of the optimization information, see
“Optimizing RAID 5 Write
Performance” on page 147 . Additional information is provided at the
appropriate step during configuration.
Creating the array
From the Create Array window, you select disk drives, then set the parameters
for the array through drop-down menu selections or check boxes. The
parameters define the details of the array and are saved in the configuration file.
The configuration file is stored on all disk drives that are members of the array
(regardless of whether the drives are in multiple enclosures). No changes are
made to the configuration until the current process is saved, so you can quit at
any time without affecting the current configuration.
After making changes to your configuration, make sure that you create a new
backup copy of the configuration file. For more information, see
“Saving the
configuration” on page 58 . Making a backup copy of the configuration lets you
quickly recover from a damaged configuration that was not self healing, and
restore everything to the last saved configuration. This preserves the definition
of the arrays, logical drives, SAN LUN mappings, and controller parameter
settings.
Stripe The process of separating data for storage on more than one disk.
For example, bit striping stores bits 0 and 4 of all bytes on disk 1,
bits 1 and 5 on disk 2, and so forth.
Stripe Size This is the number of data drives multiplied by the chunk size.
Sub-array In RAID 50 applications, this is the name given to the individual
RAID 5 arrays that are striped together. Each sub-array has one
parity drive.
Unassigned Free Space The controller keeps a map of all the space that is not assigned to
any logical drive. This space is available for creation or expansion.
Each unassigned region is individually listed.
Term Description