XADM: Log Stalls/sec Are Regularly Greater Than 0 (Zero)

ID: Q188676

The information in this article applies to:

Microsoft Exchange Server, version 5.5

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

MORE INFORMATION

Exchange often sets this value too low for large computers (less than 80). It is recommended that a significantly larger number like 256 or 512 be used.

Log stalls can have a significant impact on performance. Each log stall results in a call Sleep ( 1 ). This continues to be called until the log operation does not return the stall error.

SYMPTOMS

When monitoring the Performance Monitor counter "Database - Log Record Stalls/sec", you may notice that the value is regularly greater than zero on large computers that are under heavy load.

Performance Monitor describes this counter as: "Log Record Stalls/sec is the number of log records that cannot be added to the log buffers per second because they are full. If this counter is non- zero most of the time, the log buffer size may be a bottleneck."

WORKAROUND

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

You can reduce Log Record Stalls/sec by increasing the number of log buffers available to Microsoft Exchange. To do this, you must add the following registry parameter:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services \MSExchangeIS\ParametersSystem

Start Registry Editor (Regedt32.exe).

Locate the following key in the registry:
```
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    \MSExchangeIS\ParametersSystem 
```
NOTE: The above registry key is one path; it has been wrapped for readability.

On the Edit menu, click Add Value, and then add the following registry value:
Value Name: Log Buffers
Data Type: REG_DWORD
Value: > 80 decimal (see MORE INFORMATION below)

Quit Registry Editor.

Each buffer holds one log sector. Each log sector is equal to the sector size of your log disk (almost always 512 bytes).

Additional query words:

Keywords : XADM
Version : winnt:5.5
Platform : winnt
Issue type : kbprb