Problems hot sparing between servers

The main reason that hot sparing between integrated servers might fail is hardware compatibility. Windows Server 2003 activation may also cause problems. See the following sections for details.

Switching a Windows server from one set of integrated server hardware to another is like migrating the Windows system drive from one PC to a second PC. Differences in the required hardware abstraction layer (HAL), the basic input/output system (BIOS) level, or the devices that are installed on the two PCs can cause problems with the migration. During the initial boot of Windows on the second PC, hardware differences are detected and are handled in one of several ways:

These same hardware compatibility considerations apply when hot sparing between IXS servers, between IXA attached xSeries® servers and between iSCSI attached IBM® xSeries or BladeCenter™ servers. In order for the hot spare migration to work successfully, the hardware configurations of the two servers should be closely matched.

In order to use hot spare between IXS servers, they should be compatible types and they should have a comparable configuration of LAN adapters, etc. The Integrated xSeries server configurations table on the following web page gives the specific IXS hot spare configurations that are supported: http://www.ibm.com/eserver/iseries/integratedxseries/ixs_system_config.html.

In order to use hot spare between IXA attached xSeries servers or between iSCSI attached xSeries or IBM BladeCenter servers, it is strongly recommended that you use the same type of xSeries or IBM BladeCenter blade servers. For example, an xSeries model 236 can be a hot spare for another xSeries model 236. In addition, the xSeries servers should have a similar configuration of PCI adapters, and so on.

It may be possible to hot spare between two xSeries or blade server models that are not the same type. However, there are often significant hardware differences between xSeries or blade models. Therefore, you should test the specific combination of xSeries or blade server models that you plan to use for hot spare in this case. You should test to verify that the xSeries or blade server models have compatible hardware configurations and can be migrated seamlessly between each other before you use them for hot spare server backup in a production environment.

Each time a Windows Server 2003 server's storage spaces are switched to another hot spare integrated server, Windows Activation may be triggered. There are a limited number of free activations per license key. If activation is triggered enough times, this may require a phone call to Microsoft in order to re-activate. This can limit the speed that a server can be re-activated. Volume licenses of Windows Server 2003 can help in this case, since activation is not required.