Storage Elements; Logical Storage Elements; Persistent Storage Management Elements - HP StorageWorks NAS b2000 v2 Quick Start Manual

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Product Overview

Storage Elements

Logical Storage Elements

Persistent Storage Management Elements

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The lowest level of storage management on the NAS b2000 v2 occurs at the
physical drive level. Physical drives are grouped into RAID arrays for fault
tolerance and better performance. The end user should configure RAID arrays
using ACU. Refer to the administration guide for more details on creating RAID
arrays.
Logical Storage elements consist of those components that translate the physical
storage elements to the file system elements as presented in
NAS b2000 v2 utilizes the Microsoft Logical Disk Manager (LDM) for managing
the various types of disk presented to the file system. LDM has two types of LUN
presentation, basic disk and dynamic disk. Each of these types of disk has special
features that enable different types of management. Through the use of basic
disks, partitions or extended partitions may be created. Partitions can only
encompass one LUN up to 2 TB in size. By using dynamic disks, you can create
volumes that span multiple LUNs up to 64 TB in size. Volumes or partitions can
then be assigned a drive letter or mount point, formatted, and the presented to the
operating system for use.
Persistent Storage Manager lets the administrator make replicas of disks, called
snapshots. Snapshots enable the creation of multipurpose logical replicas of
production data without having to physically copy the data. They can be used to
immediately recover a lost file or directory, to test a new application with realistic
data without affecting the "real" data, and to serve as a source of data for backups.
Snapshots are a temporary backup of the data and are not meant to be permanent.
Snapshots use existing space from the volume, partition, or logical drive to
maintain the data required to present the original data. This space is termed the
cache file. By default the cache files consumes 10 percent of the available space of
a logical storage element. Snapshots can be read only, read-write or always keep,
and if they are shared, users can access a snapshot and edit the data. If snapshots
are shared with write access enabled, a second snapshot of the original volume
should be created. There is no backup of the original snapshot unless a second
snapshot of the volume is taken.
Figure 4. The
NAS b2000 v2 Quick Start Guide