HP P6000 Replication Solutions Manager User Guide (T3680-96089, October 2012)

IMPORTANT: Unless noted otherwise, the term disk group applies to storage system disk groups
and not to host volume disk groups that are under the control of a host OS or logical volume
manager. Storage system disk groups are managed through HP Enterprise Virtual Array interfaces
and not by logical volume managers.
Online and near-online disk categories
When a disk group is created using HP P6000 Command View, it is assigned a disk category of
online or near-online. Whenever a virtual disk is created, it assumes the disk category of its disk
group.
• Online disk category. The online disk category provides first-tier performance and reliability.
All physical disk drives in this category of disk group are dual ported, high performance Fibre
Channel drives.
• Near-online disk category. The near-online disk category provides second- tier performance
and reliability. All physical disk drives in this category of disk group are lower cost, hybrid
Fibre Channel disk drives. Hybrid drives are dual ported, FATA (Fibre Attached Technology
Adapted) drives.
Typical uses and recommended category are as follows.
Near-onlineOnlineDisk use
yesyesDisaster tolerance
yes-Disk-to-disk backup
yes-Disk-to-tape backup
-yesFrequent file access
yes-Infrequent file access
-yesHighest performance
yes-Virus attack recovery
Disk group capacity and occupancy
The capacity of a disk group is established when it is created using HP P6000 Command View
and is expressed in terms of redundancy level (Vraid). For example, the disk group named Test
might have the following Vraid-based capacities:
Vraid0: 337 GB
Vraid1: 156 GB
Vraid5: 270 GB
Vraid6: 224 GB
These capacity values are estimates only and can vary depending on the configuration.
The term occupancy refers to the amount of disk space (GB) being used in a disk group.
Disk group occupancy alarm level
The occupancy alarm level is the point (percent of capacity) at which the array issues an a disk
group occupancy warning. For example, if a disk group's capacity is 200 GB, and the occupancy
alarm level is 80%, the warning is issued when the total capacity of the virtual disks in the disk
group reaches 160 GB.
The default occupancy alarm level is 95% of capacity.
Virtual disk concepts 259