LaCie Two Big eSATA & USB
User Manual
page
3.2. Storage Policies
Before you configure the LaCie Two Big eSATA &
USB, take a minute to study the following terms.
The terms represent The LaCie Two Big eSATA &
USB configuration options or storage policies for map-
ping the physical to the virtual drives. You’ll choose
from these policies during the configuration process.
Your choice is important and impacts how best you can
use the Storage Appliance.
FAST
A storage policy configuration in which I/O processing is balanced evenly to all disks in a method known as
striping, equivalent to RAID 0. Fast offers the best performance in terms of speed but no redundancy of data.
Striping increases storage operation speed by using several disk drives in parallel. Each portion of data is divid-
ed into segments which 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.
Please check the LaCie Web site,
www.lacie.com
, for updates of the User Manual reflecting product updates.
SAFE
A storage policy configuration in which all data is stored in duplicate on separate disks to protect against data
loss due to disk failure. At least two drives mirror each other at all times, equivalent to RAID 1. Each write
goes to both disks. Safe provides the highest level of data protection but halves the amount of storage space
since all data must be stored twice. To implement the Safe storage policy, the Two Big creates two volumes.
Each volume consists of two hard disk drives that mirror each other.
BIG
A storage policy configuration in which multiple physical drives are strung together (concatenated) and treated
as one large volume. Big provides the maximum amount of storage space but no additional performance or
data redundancy. This configuration allows you to increase logical volume size beyond the capacity of individual
drives. The Two Big implements the Big storage policy by concatenating all the hard disk drives into a single
volume.
JBOD
A storage policy that grants the host PC direct access to a physical disk drive. With JBOD (just a bunch of
disks), the number of available drives is equal to the number of physical drives. JBOD is also called the bypass
mode as the host bypasses the LaCie virtualization engine to directly access the disk.
ImpOrTANT INfO:
Your LaCie Two Big
eSATA & USB comes preconfigured in
FAST
(RAID 0)
mode. For more information about
RAID levels, see chapter 7.
Understanding RAID
and Storage Policies
.
TeChNICAl NOTe:
Total disk capacity can
vary depending on the storage policy or RAID
level.
Setting up your LaCie Two Big
