HP Storage Essentials NAS Manager Software - Manual (Page 355)

Storage Essentials 5.00.01 User Guide 325
Volumes are shipped already created on HDS and Symmetrix storage systems. When you create a
volume in the management server on these storage systems, you are defining the volume as being
allocated.
Keep in mind the following:
• Some vendor's tools for HDS might round off the volume size, so that a 6.87-GB volume appears
as 7 GB (7168 MB) in the tool. The management server displays the size of the volume without
rounding. For example, assume you want to create a 14-GB (14336 MB) LUSE volume, and
according to the storage tool, you have two 7-GB LDEVs, which are really 6.87 GB (7034.88
MB). If you look at the native tool, it would be logical to assume only two LDEVs would be used
to create the 14-GB LUSE volume. The management server would use three LDEVs because each
LDEV is really 6.87 GB.
• If you are creating a volume on an HP EVA storage system, its external SMI-S provider may
round the specified number of megabytes to the nearest whole gigabyte.
• You cannot create volumes in existing storage pools on HP MSA and EVA storage systems.
• PvLinks based on HP disk partitions are not supported. Any volumes created on such PvLink meta
devices are shown as local. If you partition a regular (non-PvLink) external disk and create
volumes based on it, then volumes are recognized as external volumes.
Keep in mind the following for HDS storage systems:
• A LUSE volume on an HDS storage system is not created until you map that volume to a target
array port. In the management server, the create volume and LUN creation tasks are two
different operations. So if you want to create a LUSE volume and perform LUN creation on the
HDS box, it is a two-step process. First, use the management server to create LUSE volumes. The
management server puts volumes in the repository as grouped LDEVs. Then, create a LUN and
map a volume to a target port, by creating a host security group. See the topic, ” Creating Host
Security Groups ” on page 334 and ” Rules for Creating Host Security Groups ” on page 329.
• HDS ships some of its storage systems with volumes already created. When the software first
discovers an HDS storage system, it detects the volumes created by HDS. When you use the
software's “create a volume” feature, you are assigning the already created volume. See the
topic, ” About Provisioning on HDS Storage Systems ” on page 343 for more information.
• LUSE made up of volumes from different RAID levels are not supported. You cannot use this
product to provision this type of LUSE. Existing LUSE of this type maybe incorrectly reported.
Keep in mind the following for Engenio storage systems:
• Make sure you select a volume group that can accommodate the requested size for the new
volume.
• You can create volumes from existing free extent areas within a volume group.
• No volume-to-LUN masking is done by default, except for CLARiiON storage systems. See the
topic, ” Creating Host Security Groups ” on page 334 and ” Rules for Creating Host Security
Groups ” on page 329.
To create a storage volume:
1. Access the Create Storage Volume wizard by doing the following: