StorCase Technology InfoStation 5-Bay SATA 3Gbps RAID - Manual (Page 33)

InfoStation 5-Bay RAID User's Guide - Rev. C00 StorCase Technology, Inc.
RAID Configuration 23
Storage Policies
The following terms represent the InfoStation 5-Bay configuration options (storage policies),
for mapping physical to virtual drives. The user can choose from these policies when con-
figuring volumes (virtual drives) using the Basic Configuration Wizard or the Advanced
Configuration Wizard.
JBOD Grants the host computer direct access to physical drive(s). The number
of available virtual drives is equal to the number of physical drives.
SAFE Allows all data to be stored in duplicate on separate disk drives to protect
(RAID 1) against data loss due to drive failure. At least two drives mirror each other
at all times, equivalent to RAID 1. All write operations go to both drives.
SAFE provides the highest level of data protection, but because all data
is duplicated, storage space is halved.
To implement the SAFE policy, the Basic Configuration Wizard creates two
volumes. Each volume consists of two drives mirroring each other. The
remaining drive is specified as a Hot Spare for both volumes.
BIG Concatenates multiple physical drives into one large volume. This option
allows the user to increase logical volume size beyond the capacity of
individual drives. BIG provides the maximum amount of storage space, but
no additional performance or data redundancy.
FAST I/O processing is balanced evenly in a method known as striping, equi-
(RAID 0) valent to RAID 0. Striping increases storage operation speed as each
portion of data is divided into segments that are written to different drives
simultaneously. FAST offers the fastest performance, but no data re-
dundancy.
To implement the FAST policy, the Basic Configuration Wizard creates a
single volume of up to five (5) drives in a striped format.
SAFE and One-half of available storage space is concatenated. The other half mir-
BIG rors the first half to provide full data redundancy.
To implement the SAFE and BIG policy, the Basic Configuration Wizard
creates a volume consisting of four (4) drives. The remaining drive is
specified as a Hot Spare.
SAFE and An array of stripes is created. Each stripe consists of two (2) mirrored
FAST drives. SAFE and FAST provides the I/O load balance features of striping
(RAID 10) and the added reliability of mirrored data, equivalent to RAID 0/1. Data is
written to mirrored drives in a striped format.
To implement the SAFE and FAST policy, the Basic Configuration Wizard
creates a volume consisting of four (4) drives. The remaining drive is
specified as a Hot Spare.