Why storage task in RHEV is failing with error "IRSErrorException: Can't persist task"

Issue

• All of the storage task in RHEV is failing with below error message

2016-07-19 23:05:09,368 ERROR [org.ovirt.engine.core.bll.CopyImageGroupCommand] (org.ovirt.thread.pool-6-thread-15) [60cb4136] Command 'org.ovirt.engine.core.bll.CopyImageGroupCommand' failed: EngineException: org.ovirt.engine.core.vdsbroker.irsbroker.IrsOperationFailedNoFailoverException: IRSGenericException: IRSErrorException: Can't persist task: (u'7f44abca-c3d9-4213-a883-87239f26f00f: cannot access/create taskdir /rhev/data-center/00000001-0001-0001-0001-00000000030c/mastersd/master/tasks/7f44abca-c3d9-4213-a883-87239f26f00f: [Errno 30] Read-only file system',) (Failed with error TaskPersistError and code 413)

• It's not possible to import a virtual machine and it's failing with TaskPersistError