Instruction Manual
31
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SAT3550ESR provides the following storage policies, for mapping physical to virtual
drives. You can use the
Basic Configuration Wizard
or the
Advanced Configuration
Wizard
to choose from these policies. It is important to choose a suitable policy to make
the best use of available storage.
JBOD
This storage policy grants the host computer direct access to a
physical disk drive. With JBOD (Just a Bunch of Disks), the
number of available virtual drives is equal to the number of
physical drives. JBOD is also called the bypass mode because
the host bypasses the virtualization engine to access the drive
directly.
SAFE
This storage policy stores all data in duplicate on separate
hard disk drives in order to prevent data loss due to drive
failure. At least two hard disk drives mirror each other at all
times, equivalent to RAID 1. Every write operation goes to both
drives. SAFE provides the highest level of data protection, but
halves the amount of storage space because all data must be
stored twice.
To implement the SAFE storage policy, the
Basic
Configuration Wizard
creates two volumes. Each volume
consists of two hard disk drives that mirror each other. The
remaining hard disk drive is specified as a Hot Spare for both
volumes.
BIG
This storage policy concatenates multiple physical hard disk
drives, treating them as one large volume, in turn allowing you
to increase logical volume size beyond the capacity of
individual hard disk drives.
BIG provides the maximum amount of storage space, but no
additional data redundancy.
FAST
In the FAST storage policy, I/O processing is balanced evenly
to all drives in a method known as striping, equivalent to RAID
0. Striping increases storage operation speed by using several
disk drives in parallel, while each portion of data is divided into
segments that are written to different disks simultaneously.
Striping provides improved performance but does not enhance
reliability because there is no way to retrieve or reconstruct
data stored on a failed drive. To implement the FAST storage
policy, the
Basic Configuration Wizard
creates a single
volume of four hard disk drives in a striped format. The
remaining hard disk drive is designated as a standalone
volume using the BIG storage policy.
