Redis supports three disk flushing policies, always, everysec and no.
no: indicates no flushing and no high reliability.
always: indicates that every write operation requires flushing. This method has the best data reliability, but frequent disk flushing generates a heavy load on disk I/Os.
everysec: indicates batch disk flushing per second and adopted by eSurfing Cloud instances by default. This mode ensures excellent performance and high reliability.