Q. Is it OK to disable short filename generation on Windows Server 2008 R2 cluster nodes that use Cluster Shared Volumes (CSV)?

A. No. NTFS volumes support long filenames, but for backwards compatibility, a short filename is also generated for each file. You can disable short filename generation using the Group Policy setting Computer Configuration, Policies, Administrative Templates, System, Filesystem, NTFS, Short name creation. If you set this policy to Disabled, short file names aren't generated.

If you reboot a server after enabling this policy, CSV will stop functioning and the cluster.log will show the error

mscs::DcmAgent::PostOnline: ERROR_INCOMPATIBLE_WITH_GLOBAL_SHORT_NAME_REGISTRY_SETTING(304)' because of '\[DCM\] Failed to set flag on volume: \?Volume\{volume GUID\}'

You need to ensure short file names are enabled on your cluster nodes that use CSV to avoid breaking CSV.