Patching Issues (Windows Server AppFabric Caching)

Windows Server AppFabric cache clusters consist of several servers, cache hosts, that work together to provide a distributed cache. When one or more of the cache host servers require operating system of software updates, there are two main choices.

• Use a maintenance window when the cache cluster is down to update the cache hosts servers.

• Update one or more cache hosts at a time while the cache cluster is running.

Tip

For more information about these options and the considerations for each, see Updating Cache Servers (Windows Server AppFabric Caching).

If updates are performed during a maintenance window, any applications that attempt to access the cache cluster will get a Retry exception with an error substatus of CacheServerUnavailable. For more information, see Server Unavailability Troubleshooting (Windows Server AppFabric Caching).

If cache hosts are updated on a running cache cluster, applications might see several potential errors. The following table lists the error and error substatus of several possible DataCacheException exceptions.

Error	Error SubStatus
RetryLater	None
RetryLater	NotPrimary
RetryLater	NoWriteQuorum
ConnectionTerminated	None
Timeout	None

In general, applications should anticipate and recover from common exceptions. For more information about how to write robust AppFabric cache client applications, see Handling Errors.

See Also

Concepts

Troubleshooting Server Issues (Windows Server AppFabric Caching)