10.5. Expanding a drive link
A drive link is an aggregating storage object that is built by combining a number of
storage objects into a larger resulting object. A drive link consumes link objects in order
to produce a larger storage object. The ordering of the link objects as well as the
number of sectors they each contribute is described by drive link metadata. The metadata
allows the drive link plug-in to recreate the drive link, spanning the link objects in a
consistent manner. Allowing any of these link objects to expand would corrupt the
size and ordering of link objects; the ordering of link objects is vital to the correct
operation of the drive link. However, expanding a drive link can be controlled by only
allowing sectors to be added at the end of the drive link storage object. This does not
disturb the ordering of link objects in any manner and, because sectors are only added
at the end of the drive link, existing sectors have the same address (logical sector
number) as before the expansion. Therefore, a drive link can be expanded by adding
additional sectors in two different ways:
If the expansion point is the drive link storage object, you can perform the
expansion by adding an additional storage object to the drive link. This is done
by choosing from a list of acceptable objects during the expand operation. Multiple objects
can be selected and added to the drive link.
If the expansion point is the last storage object in the drive link, then you expand the
drive link by interacting with the plug-in that produced the object. For example, if
the link was a segment, then the segment manager plug-in that produced the storage
object expands the link object. Afterwords, the drive link plug-in notices the size
difference and updates the drive link metadata to reflect the resize of the child object.
There are no expand options.
