manage the volumes residing on dynamic disks. Other options include the
ability to delete, extend, mirror, and repair these elements.
NOTE:
See the section “Dynamic growth” in the administration guide for
additional inform ation on LUN extension and use by the operating system.
Partitions
Partitions exist as either Primary Partitions or Extended Partitions and can
be composed of only one basic disk no larger than 2 TB. Basic disks can
also only contain up to four primary partitions, or three primary partitions
and one extended par tition. In addition, the partitions on them cannot be
extended beyond the limits of a single LUN. Extended partitions allow
the user to create multiple logical drives. These partitions or logical disks
canbeassigneddrivelettersorbemountedasmountpointsonexisting
disks.Ifmountpointsareutilized,itshouldbenotedthatServicesforUNIX
doesnotsupportmountpointsatthistime. Theuseofmountpointsin
conjunction with NFS shares is not supported.
Volum
es
When planning dynamic disks and volumes there is a limit to the amount of
growth a single volume can undergo. Volumes are limited in size and are
limited to no more than 32 separate LUNs with each LUN not exceeding 2
terabytes (TB). Volumes also cannot exceed 64 TB of disk space.
The RAID level of the LUNs included in a volume must be considered. All
of the units that make up a volume should have the same high-availability
characteristics. In other words, the units should all be of the same RAID
level. For example, it would be a bad practice to include both a RAID 1+0
andaRAID5arrayinthesamevolumeset.Bykeepingalltheunitsthe
same, the entire volume retains the same performance a nd high-availability
characteristics, making managing and maintaining the volume much
easier. If a dynamic disk goes offline, the entire volume dependent on th e
one or more dynamic disks is unavailable. There could be a potential for
data loss depending on the nature of the failed LUN.
Volumes are created out of the dynamic disks and can be expanded on
the fly to extend over multiple dynamic disks if they are spanned volumes.
However, after a type of volume is selected it cannot be altered. For
example, a spanning volume cannot be altered to a mirrored volume
without deleting and recreating the volume, unless it is a simple volume.
Simple volumes can be mirrored or converted to spanned volumes. Fault
tolerant disks cannot be extended either. Therefore, selection of the volume
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