As part of the HA setup recommendation for multi AZ EFS is the recommended storage for shared HVR_CONFIG directory as logs are also written to this directory is increases the IO requirements for EFS.

The logs should be able to shifted to a different location (ideally local disk) thus allowing the full IO of EFS to be for the hub temporary files.  We understand however with the logs being on local disk the UI will not be able to display existing logs when the instance is cycled but in our situation this is of less concern as we also send applications to cloudwatch/splunk.