For all those who are not familiar with computer backups, the word “Backup” will just mean a clone of data taken for the day or an instance. Let’s go with this illustration- If suppose a backup was taken on Monday evening and nothing changed on the computer the next day, then the backup taken on that day will be almost futile, as it is going to be identical to the one created on the very first day of the week.
Despite the fact that, backups can be arranged in controlled way, it is likely that you would not. In order to get deep into “Backup” technology, let’s understand the different types of backups that can be created.
Data backups can be carried out in four ways
- Full backups
- Incremental Backups
- Differential Backups
- Mirror Backups
Full Backup-As the name itself suggests, a ‘full backup’ (also know as synthetic backup) is the very first starting point of all backups. It will contain all the data which has been configured for a backup. A “full backup” clones all the data maintained in the folders and files and so repeated full backup practices will concur simpler restore operations in a fast way, provided the data required to be backed up is limited.
- Advantages of Full backup or Normal Backup - A single backup set will maintain all the data selected from the drives. Disaster Recovery or restoration of data becomes simple, through a single backup set.
- Disadvantages of Full Backup- If the data meant for backup is enormous, then the backup time will be high and the need for more storage space allocation is required. Taking a backup of unchanged data is possible in this backup type, which will be a waste of storage resources.
Incremental Backup- In this backup variant, only those files which have changed/edited will be backed up. This backup is usually preferred by most organizations as it consumes less time to complete.
- Advantages of incremental backup- Backup time will be faster, atleast when compared to full backups. These backups require less storage space and so the need for storage media like disks; tape or network storage will be lessened. It facilitates keeping the same versions of the same file on multiple backup sets.
- Disadvantage of Incremental Backup- For restoring all files, the need for the availability of all incremental backups is essential. The seek time to restore a specific file will be more, as the search for a single backup set will take a long time.
Differential Backup- In this backup variant, only those files which change/edit after the full backup will be saved. This lessens the restore time, when compared to a full backup or an incremental backup. This type of backup is a hit among the SMBs as it cuts down the restoration time and storage space to half. To understand it in a better way let’s take a paradigm- If suppose a full backup is taken on Monday, then a differential backup is opted for rest of the days, then only those files, which have been edited/changed will be restored from Tuesday onwards.
- Advantages of Differential Backup- As expected these backups require less storage media space i.e. the need for more disks or tapes will be cut down. Backup time is usually faster than the full or incremental backups.
- Disadvantages of Differential Backup- Locating a single file from the database of differential or full backup may consume more time. Restoration of all files will also take longer, as differential backup files have to be restored at first instance and then the files/folders from full backup is done as a second instance.
Mirror Backup- Mirror Backup files will include only those files which have been changed after last full backup. It will create an exact copy of the full backup and will compress the obtained copy into a single compressed file/folder to save it with a password (I am surprised to see this new feature seen these days). The backups are maintained in a separate destination folder and it is called as a mirror of the source.
- Advantages of Mirror Backup- It is said to be the fastest backup type and creates a snapshot of only those files or folders which are selected.
- Disadvantages of Mirror backup- More storage space is required and it cannot track different versions of files.
These above said backups are being offered by a wide set of backup vendors these days. But if these backups are incorrectly used, then they can botch up the whole process of data backup, leading to data loss in an enterprise.