This is really a Microsoft Clustering question and the SRDF/CE component should not be an issue.  I believe I found the answer with Microsoft Article 304736  To summarize, it looks like you can extend a Windows 2008 and Windows 2008 R2 online but with Windows 2003 is not as clear....this is why I typically take Windows 2003 resources offline when I do an extend.   How do you know if specific applications/drives fully support transparent online extension?? So to be safe, I take them offline..   From MS Article How to perform an online extension of a data volume You can perform an online extension of a cluster data volume in Windows Server 2008 or in Windows Server 2008 R2 without stopping the cluster application(s). However, not all vendor specific applications, drivers and utilities for Windows Server 2003 fully support transparent online extension of cluster volumes. Therefore, we recommend that you test the specific hardware environment and hardware configuration to confirm that it will behave correctly before you perform the online extension in Windows Server 2003.  I really appreciate your input on this dynamox Chris
We have a number of Windows 2003 and Windows 2008 SRDF/CE Clusters.  In the past when I completed a metlun expansion and the time came to run diskpart extend, I would take the cluster resources offline and then bring online the drive to extend. Once completed, I would bring all resources online.  This has always worked but does require a short outage of 10 minutes while I complete this process.  Is this really necessary?  Do you need to take the cluster offline to extend an expanded drive?  I imagine it is the safest way to go but is it really necessary.   Since these are clusters, users want to minimize downtime.  Any documentation or thoughts would be appreciated...  I have done testing on a Windows 2008 cluster and done this process without issue but testing can often be different from production.  Thanks  Chris
Cluster Resource Offline during Diskpart Extend?