DOCUMENT:Q164261 25-FEB-2002 [winnt] TITLE :Ntbackup Causes Cache to Grow During Restore PRODUCT :Microsoft Windows NT PROD/VER::4.0 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When you run a restore of a big file with the Windows NT Backup tool you may see that the performance of the user interface and applications suffers. This happens in both the Restore and the Verify phase. You will see the problem with files bigger than physical memory. When you take a look at this in Performance Monitor, you will find that the cache is very large (from 50 percent to 90 percent of physical memory) and the process working sets have shrunk. MORE INFORMATION ================ The CreateFile API has a flag, FILE_FLAG_SEQUENTIAL_SCAN, that is especially useful when copying files. It tells Cache Manager not to try to increase the file cache when requests for this handle arrive. Hence, Memory Manager does not have to shrink the applications working set to accommodate the bigger cache. Although Windows NT Backup uses this flag during Backup, it does not do so in the Restore phase. STATUS ====== Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces): S E R V P A C K Additional query words: ====================================================================== Keywords : Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : :4.0 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.