In the early days, it seemed like breathing on a Windows server resulted in the need for an administrator to reboot the server. Over the years, Microsoft has made great strides in reducing the number of reboots necessary to manage a Windows server, including Windows Server 2003. However, patching a Windows server can still result in a required reboot, thus dashing the "the five nines" goal of many organizations (i.e., 99.999 percent availability). Enter hotpatching.
Although hotpatching will not completely eliminate server reboots, the services provide a mechanism to update system files without rebooting and without stopping services and processes. Hotpatching has some limitations, which include:
- Hotpatching currently works only on 32-bit versions of Windows.
- Hotpatching has some compatibility issues with some non-Microsoft applications. See Microsoft Knowledge Base article 922612 for more information.
A hotpatch contains two versions of an update -- what Microsoft calls a "cold patch" and a "hot patch" bits. You can hotpatch a file by following this three-step process:
- The coldpatch portion of the update replaces the old binary file.
- The hotpatch portion of the update is then loaded into the image of the defective binary file.
- An instruction above the defective function is inserted, which redirects subsequent calls to the updated function.
Users can obtain hotpatch-enabled update packages from Microsoft's Download Center. For more information about hotpatching, visit Microsoft's TechNet site.
Miss a column?
Check out the Windows Server 2003 archive, and catch up on the most recent tips from this newsletter.
Stay on top of the latest WS2K3 tips and tricks with our free Windows Server 2003 newsletter, delivered each Wednesday. Automatically sign up today!
