What Is Disk Mirroring?

The term "disk image" generally has two different meanings. One refers to copying to storage devices with the same function to enhance data integration, enhance fault tolerance, and increase throughput (such as RAID). At this time, the corresponding English is generally Disk Mirror, hereinafter referred to as disk mirror . Another meaning is to copy to a different device or data format, mainly for data backup. At this time, the corresponding English is generally Disk Image, which is hereinafter referred to as disk image . Both are commonly referred to as "mirroring" or "disk mirroring" in use.

Disk Mirroring-In order to avoid disk drive failure and data loss, a disk mirroring function has been added. To achieve this function, an identical disk drive must be added under the same disk controller. When the disk mirroring method is used, after each time data is written to the primary disk, the data needs to be rewritten to the backup disk so that the two disks have identical bitmaps. Think of the backup disk as a mirror of the primary disk. When the primary disk drive fails, the host can still work normally after the switch because of the backup disk. Although disk mirroring has achieved fault tolerance, it has reduced the disk utilization to 50% and failed to improve the server's disk I / O speed. ^[1]

Disk mirror (Disk Mirror) refers to the real-time replication of data on a logical disk volume to several logical disk volumes to ensure its continuous availability, consistency and accuracy.

Disk image refers to saving the complete content and structure of a certain storage device (such as a CD) as a computer file, so these files are usually very large. Usually there is only one file, which contains many files

Disk mirroring has become an everyday application at many enterprise workstation and server levels. If you want to "must have now" worldwide to provide a high level of security, remote users, minimal downtime and data loss tolerance, using disk mirroring is perfect. Disk mirroring plays a vital role in backup, data storage management, and response to disaster recovery and security incidents. In many enterprises, disk mirroring is the only technology used in these situations.

Disk mirroring software has been backing up and restoring data for many years, and the application of disk mirroring in this area has not reached the broad market. Although Symantec's Gost and driver mirroring technologies are still popular, there are also other disk mirroring vendors, such as Acronis Inc., LSoft Technologies, and UltraBac Software, which are more prominent in this area. These products look no different from traditional data backup software, but they back up and restore data at a lower level: drive sectors. ^[2]