Q283217: Registry Hive Fragmentation Fix May Cause Excessive SAM Size
Article: Q283217
Product(s): Microsoft Windows NT
Version(s): 4.0 SP5,4.0 SP6,4.0 SP6a
Operating System(s):
Keyword(s): kbRegistry kbWinNT400PreSP7Fix
Last Modified: 11-JUN-2002
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The information in this article applies to:
- Microsoft Windows NT Server versions 4.0 SP5, 4.0 SP6, 4.0 SP6a
- Microsoft Windows NT Server, Enterprise Edition versions 4.0 SP5, 4.0 SP6, 4.0 SP6a
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IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
Q256986 Description of the Microsoft Windows Registry
SYMPTOMS
========
The SAM registry hive size in Windows NT 4.0 may increase rapidly after you
update your computer with Service Pack 5 (SP5), Service Pack 6 (SP6), or Service
Pack 6a (SP6a).
CAUSE
=====
This problem can occur because the Windows NT 4.0 registry cell allocation
behavior reduces SAM fragmentation. This behavior is described in the following
Microsoft Knowledge Base article:
Q197632 Registry Hive Fragmentation Leads to Excessive Size
Although this fix does help to resolve this problem, the fix can increase the SAM
size in some situations where there is an excessive number of global groups with
many members that rarely change. In this environment, the updated behavior of
over-allocating to create larger cells that can be reused for future growth does
not work and actually orphans larger fragments, which leads to excessive SAM
sizes.
RESOLUTION
==========
A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem. This fix may receive additional
testing at a later time, to further ensure product quality. Therefore, if you
are not severely affected by this problem, Microsoft recommends that you wait
for the next Windows NT 4.0 service pack that contains this fix.
To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. For a complete list of Microsoft Product Support Services
phone numbers and information about support costs, please go to the following
address on the World Wide Web:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.
The English-language version of this fix should have the following file
attributes or later:
Date Time Size File name Platform
----------------------------------------------------
01/03/2001 05:18p 936,640 Ntoskrnl.exe Intel
STATUS
======
Microsoft has confirmed this to be a problem in Windows NT 4.0 SP5.
MORE INFORMATION
================
WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.
NOTE: The fix referenced in this article configures SAM cellsize allocation to
the original algorithm, but does not enable the user to configure
RegistryAdjustCellSize. The fix to allow the registry change described below is
included in the following hotfix and should be applied if you need to alter the
algorithm behavior. For additional information, click the article number below
to view the article in the Microsoft Knowledge Base:
Q294345 Registry Hive Fragmentation Behavior Is Not Configurable
A registry setting is added to Ntoskrnl.exe to make the Q197632 allocation
granularity change optional. To disable the Q197632 allocation granularity
setting:
1. Click Start, click Run, type "regedit32" (without the quotation marks) in the
Open box, and then press ENTER.
2. Locate and click the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
3. On the Edit menu, click Add Value, and then add the following registry value:
Value name: RegistryAdjustCellSize
Data type: REG_DWORD
Radix: Hexadecimal
Value: 0x0 revert to original hive cell allocation granularity, 0x1 use
Q197632 hive cell allocation granularity.
Default: 0x1
4. Quit Registry Editor.
5. Restart your computer.
Additional query words: ntoskrnl 283217
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Keywords : kbRegistry kbWinNT400PreSP7Fix
Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp6 kbWinNTSEnt400sp5 kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400search kbWinNTSEnt400SP6a
Version : :4.0 SP5,4.0 SP6,4.0 SP6a
Hardware : ALPHA x86
Issue type : kbbug
Solution Type : kbfix
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