You might face a problem with your TIC where a Cache engine is down and won't back up.
If your GRID is on version 5.7.23 or earlier, you might come across this issue. While trying to restore the CE, it fails the CE from joining the cluster.
To resolve this issue, along with storage format you will need to upgrade to version 5.7.25b41 or the latest versions available (PeerApp 6.x, 7.x) that has a fix to this and other known bugs.
Following are the links to the versions, credentials can be found in Access Guide.
After upgrading to version 5.7.25b41, add the following new configuration to the cluster which is part of the bug fix;
In order to get your system upgraded, raise a support ticket asking for the upgrade mentioning a version if you have a preference, and specifying a preferred maintenance window when you will be available for the upgrade. Know that a MW can be between 2-4 hours.
Contact PeerApp support if you need help with upgrading.
Make sure all CEs are up and all volumes are mounted and CE starts serving traffic as per the normal trend. Monitor the GRID for total downstream, cache-out, BHR, and logical view for performance comparison