Question

Discuss the differences between conducting differential and incremental backups with emphasis on database backups and restore and reliability (do they always work?).

Answer 1

Full backup of data of a company/organisation takes a lot time and space. More the size of data more the time and space. It become a costly process over the time as the company grows in size, if anybody thinks to take full backup of his precious data. Also there is some wastage of the resources as every day whole data is not changed; merely some part of data get changed.

Here the concept of Differential backup and Incremental backup is useful.

What is differential and incremental backup?
Differential backup takes a copy of all data that were changed since the last full backup. Say in a company, Full backup is taken only on Sunday. Differential backup is taken on other day at midnight say at 1 A.M.

Whereas incremental backup takes a copy of data changed / added since the last incremental backup. Say in a company, Full backup is taken only on last day of the month. Incremental backup is taken on every day except the last day of month at midnight say at 1 A.M. So backup taken on 3rd of month will contain the data of 1st and 2nd of month.

If database in an application is used for high write activity, taking full backup everyday is best option.

Differential backup is good for following situation
1. If you need fast restoration of data
2. It only needs only two backup data, last full back up and the differential backup of the day, you want to restore

Incremental backup is good for following situation
1. If you have less storage capacity.
2. You don't need frequent and very fast recovery.