Sometimes there can be issues with Block storage due to unforeseen events such as a host hardware incident or similar that can leave the blocks in a weird state.  In most cases, these can be resolved from the customer control panel with some simple actions.  Of course, if the method described here does not resolve the issue with your storage device, please reach out to support for further assistance.

First, if you have access to the OS of the server, please log in and verify that the Block storage is not visible from the server.  If it is, you'll want to unmount the storage device if it is still mounted.  Next, you'll want to ensure you are logged into your Cloud Control panel at mycloud.rackspace.com.  Once there, you'll want to navigate to the storage tab, and select the Cloud Block Volumes link from the dropdown.

Once the page loads you can locate the block with the issue.  You may wish to note where the block is mounted on the server, which you can do from the block details page after clicking on the volume name.

From the volumes page, you can click the gear icon next to the affected volume to detach it.

This can also be performed via the actions drop down in the volume details page.

This will remove the block from your server, and clean up any lingering attachments or backend processes associated with the block.  This gives us a fresh slate to start from, and removes any broken items that may have resulted from whatever issue caused the block to misbehave.

Finally, once the detach completes, you can then select the same gear icon or actions dropdown, and this time select 'attach volume'.  Choose the correct server, and if necessary fill in the attachment point as before.  This should attach the block in the same fashion as it was previously, and all data that was written to the disk before the issue occurred should be available as normal.

Again, if the above instructions do not resolve the issue with a block storage device, please feel free to look through the community for further suggestions, or reach out to Rackspace support via your preferred method, be it phone, chat, or ticket.