Dell PowerEdge RAID Controller H800 - Manual (Page 31)

Storage Controller Features 31
Reconfiguring Virtual Disks
An online virtual disk can be reconfigured in ways that expands its capacity
and/or change its RAID level. Spanned virtual disks such as RAID 10, 50, and
60 cannot be reconfigured.
Online Capacity Expansion (OCE) can be done in two ways. The first way is
to expand the volume using free space already in the disk group. For example,
if there is a single virtual disk in a disk group and free space is available, the
virtual disk’s capacity can be expanded within that free space. If a virtual disk
is created and it does not use the maximum size of the disk group, free space
is available and OCE is possible. Free space is also available when a disk
group’s physical disks are replaced by larger disks using the Replace Member
feature. The second method by which OCE can be done is by adding physical
disks to the disk group and using OCE to incorporate free space from the
newly added disks into the virtual disk.
RAID Level Migration (RLM) refers to changing a virtual disk’s RAID level.
Both RLM and OCE can be done at the same time so that a virtual disk can
simultaneously have its RAID level changed and its capacity increased. When
a RLM/OCE operation is complete, a reboot is not required.For a list of
RLM/OCE possibilities, see Table 3-2. The source RAID level column
indicates the virtual disk RAID level before the RLM/OCE and the target
RAID level column indicates the RAID level after the operation has
completed.
NOTE: If you configure 64 virtual disks on a controller, you cannot perform a
RAID level migration or capacity expansion on any virtual disk.
NOTE: The controller changes the write cache policy of all virtual disks undergoing
a RLM/OCE to Write-Through until the RLM/OCE is complete.
PERC7.2_UG.book Page 31 Thursday, March 3, 2011 2:14 PM