Specifications

22 en | RAID Functions: Introduction SCSI to SATA RAID Subsystem | Administrator’s Manual
F.01U.027.802 | V1 | 2006.11 Bosch Security Systems
When a logical drive is used as a member of a logical volume, this logical drive can no longer
be partitioned in “View and Edit Logical Drives.” Instead, the Logical Volume can be divided
into eight partitions in “View and Edit Logical Volume.”
The procedure for partitioning a logical volume is the same as that for partitioning a logical
drive. After the logical volume has been partitioned, map each partition to a host ID/LUN to
make the partitions available as individual drives.
As members of a logical volume, all logical drives will be forced to adopt a consistent write
policy. Whenever the write policy of a logical volume is changed, for example, the correspond-
ing setting in its members will also be changed.
1.6.5 RAID Expansion with Logical Volume?
The Logical Volume can also be expanded using the RAID expansion function. The concept of
expanding a logical volume is similar to that of expanding a logical drive. To perform RAID
expansion on a logical drive, replace each member physical drive with a drive of larger capac-
ity or add a new drive, then perform logical drive expansion to utilize the newly added capac-
ity.
To perform RAID expansion on a logical volume, expand each member logical drive, then per-
form “RAID Expansion” on the logical volume.
Steps to expand a Logical Volume:
1. Expand each member logical drive.
2. Expand the logical volume.
3. Map the newly added capacity (in the form of a new partition) to a host LUN.
1.6.6 A Logical Volume with Logical Drives of Different Levels?
Multi-level RAID Systems
RAID (0+1) - this is a standard feature of Bosch RAID controllers. It brings the benefits of
RAID1 (high availability) and RAID0 (enhanced I/O performance through striping). Simply
choose multiple drives (the number must be even; i.e., a multiple of two) to compose a RAID1
logical drive, and RAID (0+1) will be automatically implemented.
RAID (1+0) or RAID 10 - a logical volume is a multi-level RAID implementation. A logical volume
is a logical composition, which stripes data across several logical drives (the RAID0 method).
A logical volume with several RAID1 members can be considered as a RAID (1+0), or RAID 10
volume.
RAID (3+0) or RAID 30 - a logical volume with several RAID3 members.
RAID (5+0) or RAID 50 - a logical volume with several RAID5 members.
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NOTICE!
• If a logical unit has already been partitioned, and you wish to expand its capacity, the
added capacity will be appended to the last partition. You will not be able to proceed
with expansion using a firmware version earlier than 3.27 when the unit already has eight
partitions.
• Unless you move your data and merge two of the partitions, you will not be allowed to
expand your logical volume. This is a precautionary limitation on logical unit expansion.