HP NetRAID 1Si Controller - Manual (Page 130)

Chapter 6 Capacity Expansion
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About Online Capacity Expansion under Windows NT describes the
Online Capacity Expansion feature. This feature allows new storage
capacity to be added to an existing logical drive and put online for use
without restarting the server.
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Preparation Steps for Windows NT explains how you enable Virtual
Sizing and how to partition your drives to use this feature of HP NetRAID.
•
Expanding Capacity Online under Windows NT describes how to use
the Online Capacity Expansion feature to add physical drives to your
system without restarting the server.
•
Expanding Capacity under Windows NT with Virtual Sizing Disabled
describes how you can add disk capacity to an existing logical drive if you
didn’t set up your logical drive initially to use the Online Capacity
Expansion feature.
About Online Capacity Expansion under Windows NT
Normally, adding capacity requires shutting down the server to reconfigure/restore
an existing volume or to add the new storage space as a new volume. Using the
Online Capacity Expansion feature allows you to expand an existing logical drive
without shutting down the server.
NOTE The additional capacity will have a different drive letter than
the original logical drive. If the expanded capacity and the
original capacity must share the same drive letter, you must
restart the HP NetServer. For more information about drive
letters, see "Expanding Capacity Online under Windows NT"
later in this section.
Capacity Expansion is enabled separately on each logical drive. When enabled,
the adapter presents to the operating system a logical drive of 500 GB. However,
only a part of the 500-GB logical drive exists as actual physical storage. You
configure logical drives to use only the actual physical space, while the virtual
space allows room for online expansion.
For example, assume you have one logical RAID-5 drive built from four physical
hard disk drives of 9 GB each; the result is 27 GB of actual storage space. If you
enable Virtual Sizing for this logical drive, then the operating system sees a
logical drive of 500 GB. Only the first 27 GB are real, 9 GB are used for parity,
and the last 464 GB are virtual. Since there is unused logical drive space, the
physical storage of 27 GB can be expanded online, but the total logical drive
remains at 500 GB.