Disk Groups and Virtual Disks 536Disk Groups and Virtual DisksFollowing is a list of terms used throughout this chapter:• Disk Group — A set of physical disks that are logically grouped andassigned a RAID level. Every disk group provides the overall capacityrequired to create one or more virtual disks.• Virtual Disk — A logical component created to enable hosts to accessstorage on the storage array. A virtual disk is created from the capacityavailable on a disk group and appears as one logical component eventhough it is created from more than one physical disk.• Storage Partitioning — Logical division of a storage array into entitiesconsisting of one or more virtual disks that can be accessed by a single hostor shared among hosts that are part of a host group.• Unconfigured Capacity — Physical disks that are not already assigned toa disk group.• Free Capacity — Space in a disk group that has not been assigned to avirtual disk.• Standby Hot Spare Drive — Physical disk that has been assigned as a hotspare drive and is available to take over for any failed physical disk.• In-use Hot Spare Drive — Physical disk that has been assigned as a hotspare drive and is currently taking over for a failed physical disk.• Snapshot Virtual Disk — Point-in-time image of a virtual disk in astorage array.• Snapshot Repository Virtual Disk — Virtual disk containing metadata andcopy-on-write data for a particular snapshot virtual disk; automaticallycreated when the snapshot virtual disk is created.• Consistency Check — Background operation that checks the parity ofvirtual disks.
