It is also possible to create a BIG volume using only a single hard disk drive
connected to Port 0, and then increase the storage capacity of the volume later by
adding another hard disk drive to Port 1 and pressing the Mode Change push-
button. The new disk blocks of
Port 1 will be concatenated to the end of the disk
blocks of Port 0, and any data that is stored on the existing BIG volume will be
preserved. However, it is not possible to expand an existing BIG volume by
adding another hard disk drive to Port 0 and still
preserve any existing data on
that volume.
JBOD
The JBOD (Just a Bunch of Disks) storage policy enables each hard drive to be
seen separately as one drive. When using a SATA host controller, JBOD should
only be used if the SATA host controller provides Port Multiplier (PM) support. If
a
host is not PM-aware, only a single drive is presented (drive 0). No such limitation
if using a USB host connection. JBOD storage policy is available in the SteelVine
Manager for a standalone (non-cascaded) Storage Processor or the top-level
node of a cascaded configuration, but not for subordinate nodes. Even
though
you can use the switch to select JBOD mode. In a JBOD configuration, the
SteelVine Storage Reference Design directly exposes each physical drive.
FAST(RAID0)
The FAST storage policy distributes access across all hard disks, also called
striping (equivalent to RAID 0). FAST presents the best data speed but no data
redundancy. FAST storage policy accelerates hard disk operating speed by using
many disks in parallel. Hard drive data segments are written to different disks
simultaneously which increases performance while sacrificing data redundancy.
To implement the FAST storage policy, the SteelVine Storage Processor creates a
single virtual volume that is striped
across both hard drives, with a storage
capacity that is equal to the sum of both hard disk drives.
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