NAS b2000 - Quick Start Guide

Product Overview
NAS B2000 Quick Start Guide 1-9
COMPAQ CONFIDENTIAL
Writer: Darrell Washington File Name: b-ch1 Product Overview.doc
Codename: Collins Part Number: 292283-001 Last Saved On: 5/30/02 9:38 AM
Storage Elements
The lowest level of storage management on the NAS B2000 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.
Virtual Storage Elements
Virtual Replicator (VR) provides volume virtualization for the NAS device by
allowing for the creation of virtual disks from VR pools containing the LUNs. VR
pools are logical abstractions that aggregate the disk space from one or more LUNs
into a large set of disk blocks. From the pool of blocks, VR virtual disks are created
and presented to the operating system as New Technology File System (NTFS)
volume pools. Virtual disks can be enlarged at a later time when there is a need for
more space.
When using VR, the following constraints apply:
• Windows 2000’s Logical Volume Manager (LVM) should not be used to manage
VR disks. The two management tools do not have an awareness of each other and
compatibility issues can arise between the two management tools.
• VR pools can consist of a maximum of eight storage units. Thus, a pool can
consist of a maximum of eight separate LUNs. Each LUN cannot exceed 1 TB in
size.
• A pool may contain a maximum of 8 TB of disk space, and the maximum virtual
disk size is 2 TB.
• There is a limit to the number of virtual disks that can be carved out of a VR
pool. Currently, a maximum of eight virtual disks can be carved out of a single
pool.
• To be accessible, each virtual disk must be presented as a drive letter or a
mount-point on the NAS device for users and on the operating system. Although
it is possible to create a virtual disk and not map it to a drive letter or
mount-point, neither the users nor the administrator would have access to the
storage space contained within that virtual disk.