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Running Win 2008, I'd like to extend the volume of a SAN attached drive that is part of a failover cluster. The SAN team has allocated additional drive space which is being seen by Windows Storage Manager. However, the option to "Extend Volume" is disabled, so is the ability to turn it into a dynamic disk.

Is the ability to extend volumes when part of a failover cluster disabled or not available when it's part of SAN attached storage?

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Just my 2 cents, but in all SAN drives i have seen (NetApp and EMC) there's specific software installed in the server. Usually I can open an MMC console and, with that software, extend it without problems. Sometimes the software didnt show on the start menu. Hope this helps. – Carlos Garcia Dec 21 '10 at 18:06
up vote 2 down vote accepted

Online volume extension is definitely supported for the scenario you describe, provided the increased size of a SAN attached drive is added so that the original volume as seen by the servers gets additional free space starting at the end of the existing partition. This KB article is for older versions of Windows Server but it details the procedure to follow for either online or offline expansion. This refers to using DiskPart not the GUI Disk Manager\Storage Manager but this should work with Windows 2008 ( as per this MSDN Blog entry ). If you are not getting the option then something else appears to be wrong, are you certain that the additional space is actually contiguous? The only other thing I can think of is that the volume size is too large to extend (2TB already and you are trying to make the shared volume bigger).

You shouldn't be using Dynamic Disks with failover clusters without third party software, that is why the Dynamic Disk option is disabled, the blog link above discusses this too.

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U can probably use DiskPart or a Live CD of a specific Linux distro like gparted-live-0.6.3-3.iso (Impressive for VM) but before that, check de software or search in the SAN documentation/web for the software to expand it. – Carlos Garcia Dec 21 '10 at 18:12
I did not do that, and pretty much followed his steps above. I've used gparted-live and recommend it for anyone looking to do partition manipulation, it has worked well for us when we've needed it. – Bye Sep 28 '11 at 4:54

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