Windows NT Partitioning Rules During Setup (138364)
The information in this article applies to:
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Professional
- Microsoft Windows NT Server 3.1
- Microsoft Windows NT Server 3.5
- Microsoft Windows NT Server 3.51
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Workstation 3.1
- Microsoft Windows NT Workstation 3.5
- Microsoft Windows NT Workstation 3.51
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Advanced Server 3.1
- Microsoft BackOffice Small Business Server
This article was previously published under Q138364 SUMMARY During the installation of Windows NT, Setup determines the
best partitioning scheme to use based on the existing partition table entries
and where you choose to install Windows NT. Windows NT Setup restraints
restrict the boot partition of up to 4 GB. The limit may be smaller depending
on disk geometry. The actual value that is used as the limit is whatever Setup
believes to be 1024 cylinders worth of disk space. Sometimes this is 1 GB, 2
GB, or 4 GB, but can be some other value depending on the make, model, and
configuration of the hard disk adapter in use. This is the amount of space with
which the text-mode portion of the installation can work. From this amount, you
can create partitions that do not exceed 4 GB because the partition must first
be formatted FAT and this file system has a limit to 4 GB. Note: Windows 2000 and later operating systems no longer have a 4GB
system / boot partition limit, however the partition types that Setup creates
still follow the rules described in this article.
For additional information, click the following article numbers to view the
articles in the Microsoft Knowledge Base: 119497
Boot Partition Created During Setup Limited to 4 Gigabytes
224526 Windows NT 4.0 Supports Maximum of 7.8-GB System Partition
These articles explain rules to consider before you
install Windows NT 4.0 on computers that contain large hardware RAID-5 drive
arrays if you want to use the full contiguous capacity of these large arrays
after Windows NT4.0 is installed. MORE INFORMATION When you use a Hardware RAID-5 configuration, it is very
important to understand how Windows NT partitions your drive during Setup in
order to maintain maximum contiguous capacity of the large Array for user data
after Windows NT is installed. Setup follows these rules: Rule 1 If no partitions pre-exist on the drive, Setup makes the primary
partition the size you specify for Windows NT (up to 4GB). Rule 2 If a primary partition already exists, and you choose to install
Windows NT in an unformatted free space, you are prompted for the size of the
partition to create (up to 4 GB). After you choose the partition size, Setup
creates the largest extended partition possible (up to 7.8 GB if using a 63
sectors/track, 255 tracks/cylinder translation scheme) and creates a logical
drive within the extended partition of the size you choose. After Windows NT is
installed, the unused extended partition space can be used for additional
logical drives. Rule 3 If a primary and extended partition already exist and free space
in the extended partition is selected, Windows NT creates a new logical drive
of the size specified by you. Rule 4 If a primary and extended partition already exist and free space
is available and selected outside of the extended partition, Windows NT creates
another primary partition of the size the you choose (up to 4GB) for Windows NT
to be installed in. There are two possible workarounds: - Prior to installing Windows NT, use MS-DOS FDISK to create
an extended partition of 250 MB, then create a logical drive of 250 MB within
the extended partition. When you install Windows NT, select this partition as
the target to install Windows NT in.
-or- - Install Windows NT into the first primary MS-DOS FAT
partition. After Windows NT is installed, run Disk Administrator and create a
second primary partition of 250 MB. Re-install Windows NT into this second
primary partition and then delete the first Windows NT installation from the
first primary MS-DOS partition.
EXAMPLE You have four 2-GB drives configured in a hardware RAID-5
configuration for a total capacity of 6 GB and want a 5.5-GB NTFS partition for
user data after Windows NT is installed. You have MS-DOS pre-installed on a
250-MB primary partition prior to installing Windows NT and want to keep this
intact. You decide to install Windows NT into a separate NTFS partition and
create a 250-MB partition from free space during Windows NT Setup.
Using rule 3 above, Windows NT creates an extended partition of 4 GB, then
creates a 250-MB logical drive within to install Windows NT on. After Windows
NT is installed, Disk Administrator shows the following:
C: 250 MB FAT
D: 250 MB NTFS (logical drive)
3.750 GB extended partition space (free)
1.750 GB Free space
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6.0 GB total usable space in hardware raid-5 configuration.
The problem is that the 2 free spaces cannot be combined to equal
the 5.5-GB partition space wanted for user data.
Modification Type: | Major | Last Reviewed: | 5/7/2003 |
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Keywords: | kbinfo KB138364 |
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