• Microsoft Windows NT Workstation version 3.5
• Microsoft Windows NT Server version 3.5
• Microsoft Windows 2000 Professional
• Microsoft Windows 2000 Server
• Microsoft Windows 2000 Advanced Server
• Microsoft Windows NT 3.51 or later

Summary
The total amount of space that may be consumed in paged pool and disk space by Registry data (the Hives) is limited by the Registry Size Limit, or RSL. RSL is a kind of "global quota" for Registry space.

More Information
By default, RSL is 25 percent of the size of paged pool. Setting up the size of paged pool (see PagedPoolSize value of the Registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Memory Management
also affects the size of RSL.

You can also manually set the RSL:

1. Run the Registry Editor (REGEDT32.EXE.)
   

   WARNING:
   Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

2. Locate the key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control.
   
3. Modify the value RegistrySizeLimit (create it first it if it does not already exist) to reflect the desired size, in terms of bytes.
   
   NOTE: RegistrySizeLimit must have a type of REG_DWORD, and a data length of 4 bytes, or it is ignored. If you set the value RegistrySizeLimit to less than 4 megabytes (MB), it is forced up to 4 MB. If you set it to greater than about 80 percent of the size of paged pool, it is set down to 80 percent of the size of paged pool (it is assumed that paged pool is always more than 5 MB.) If you set it to 0xffffffff the maximum size allowable (or 80 percent of paged pool, up to 102 MB) is set.
   
4. Shut down and restart Windows NT for changes in RSL to take effect.

In Windows NT 4.0, and Windows NT 4.0, Terminal Server Edition, the maximum paged pool size is 192 MB, so RSL can be a maximum of 153.6 MB. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

Q142719 NT Reports Out of Resources Error When Memory is Available

Q126402 PagedPoolSize and NonPagedPoolSize Values in Windows NT

Additional Notes on RSL
RSL sets a maximum, not an allocation (unlike some other such limits in the system.) Setting a large RSL will NOT cause the system to use that much space unless it is actually needed by the Registry. It also does NOT guarantee that that much space will be available for use in the Registry.

In Windows NT version 3.1, paged pool defaults to 32 MB, so the default RSL is 8 MB (enough to support approximately 5000 user accounts.) In Windows NT 3.5, paged pool can be set to a maximum of 128 MB, so RSL can be no larger than about 102 MB (enough to support approximately 80,000 users; however, other system limitations might keep this number of users considerably lower.)

RSL includes space in the hives themselves, as well as some of the Registry's runtime structures. Other runtime structures are either billed against standard quota, or are protected by size limits and serialization.

To ensure that you can always at least boot and edit the Registry if you set RSL incorrectly, quota checking is not turned on until after the first successful loading of a hive (that is, loading a user profile.)

For all but a few domain controllers, RSL never needs to be changed.

The limitations imposed by RSL are approximate.

For more information on the Registry size limit, search on the keyword "RegistrySizeLimit" in the Windows NT Registry Entries Help file found in the Windows NT version 3.5 Resource Kit, or query on the following keyword in the Microsoft Knowledge Base: