Information Technology Reference
In-Depth Information
Enhanced Manageability
Virtual disk management systems typically provide a simple graphical user
interface for disk management and administration. This allows simple,
almost error-free administration of complex disk configurations and file
systems.
The graphical interface usually includes a visual representation of the physi-
cal disks and virtual disk file systems. In addition, it typically supports drag-
and-drop capabilities that allow quick configuration changes.
Concatenated Virtual Devices
Unlike the standard Solaris file system, which consists of a single partition
(slice), a concatenated virtual file system consists of two or more slices. The
slices can be on the same physical disk or on several physical disks. The slices
also can be of different sizes.
Concatenation
implies that the slices are addressed in a sequential manner.
That is, as space is needed, it is allocated from the first slice in the concate-
nation. Once this space is completely used, space is allocated from the sec-
ond slice, and so on.
The main advantage of a concatenated virtual device is that it provides means
for using slices that might otherwise be too small for use. In addition, con-
catenation using more than one physical disk provides some load balancing
between the disks and can result in head movement optimization.
However, using multiple disks increases the chance that a failure of any one
disk will result in the failure of the virtual device.
Striped Virtual Device
A
striped virtual device
, like a concatenated virtual device, can consist of two
or more slices. The slices can be on the same physical disk or on several phys-
ical disks. The slices can also be of different sizes.
Unlike a concatenated device, the slices are addressed in an interleaved man-
ner. That is, as space is needed, it is allocated as a block from the first slice,
and then a block from the second slice, and so on.
The main advantage of a striped device is that when the slices are on several
physical disks, it provides an increase in performance because it allows mul-
tiple simultaneous reads and writes. This is because each physical disk in the
