If the filesystem used is supported, it should work in theory. See here: http://docs.splunk.com/Documentation/Splunk/6.5.1/Installation/Systemrequirements#Supported_file_systems
I suspect that it isn't a supported filesystem, which will cause Splunk to run something called "locktest" on it. If Splunk is unable to acquire a lock then it will not allow you to utilize the storage. See here: https://docs.splunk.com/Documentation/Splunk/6.5.1/Troubleshooting/CommandlinetoolsforusewithSupport#locktest
Lastly, I don't know much about Google Cloud Storage FUSE, but i suspect performance may be an issue. I'd use caution even if it does work correctly. Based on what i'm reading here: https://github.com/GoogleCloudPlatform/gcsfuse#latency-and-rsync I'd be concerned with performance characteristics.
... View more