Special retention periods are specified in a backup policy for the first backups that are generated every week, every month, and every year. Special retention periods help you meet compliance requirements for data security. This topic describes what special retention periods are and how to configure special retention periods.
What are special retention periods?
In addition to the general retention period specified in a backup policy, you can specify longer retention periods for the first backups that are generated every week, every month, and every year to meet compliance requirements for data security. You can configure special retention periods of weekly, monthly, and yearly backups at the same time in a backup policy. If multiple retention periods conflict, the longer retention period takes effect. Backups with special retention periods are marked as special backups in the console.
If you do not configure special retention periods but you need to save backup versions for a long time, you can only extend the general retention period. Special retention periods provide more flexible lifecycle management capabilities for your backups.
The following types of special retention periods are supported:
Special retention period of weekly backups
Among the backup versions created by a backup policy between 00:00 on each Sunday and 00:00 on the next Sunday, the first backup is selected as a special backup and is retained for the specified period of time.
Special retention period of monthly backups
Among the backup versions created by a backup policy between 00:00 on the first day of each month and 00:00 on the first day of the next month, the first backup is selected as a special backup and is retained for the specified period of time.
Special retention period of yearly backups
Among the backup versions created by a backup policy between 00:00 on January 1 of each year and 00:00 on January 1 of the next year, the first backup is selected as a special backup and is retained for the specified period of time.
Examples of special retention periods
The following examples describe the working mechanism of special retention periods.
Example 1: Create special retention periods
Data is backed up once a day at 01:00. General backups are retained for seven days. You set the special retention period of weekly backups to five weeks, the special retention period of monthly backups to three months, and the special retention period of yearly backups to two years. The following list describes the retention periods of backups that are generated from January 1 to January 10.
Yearly backups
The backup generated on January 1 is retained for two years. The special retention period of yearly backups takes effect.
Monthly backups
The backup generated on January 2 is retained for three months. On January 1, the special retention period of yearly backups conflicts with the special retention period of monthly backups. In this case, the special retention period of monthly backups is postponed to take effect on January 2.
Weekly backups
The backups generated on Monday, January 3 and Sunday, January 9 are retained for five weeks. On Sunday, January 2, the special retention period of weekly backups conflicts with the special retention period of monthly backups. In this case, the special retention period of weekly backups is postponed to take effect on January 3.
General backups
The other backups generated from January 1 to January 10 are retained for seven days.
Example 2: Modify special retention periods
At 00:00 on January 11, you change the special retention period of monthly backups to six months and the special retention period of yearly backups to three years. The following list describes the retention periods of backups that are generated from January 11 to January 20.
Yearly backups
The backup generated on January 11 is retained for three years. The special retention period of yearly backups is changed and takes effect at 00: 00 on January 11.
Monthly backups
The backup generated on January 12 is retained for six months. The special retention period of monthly backups is changed and takes effect at 00: 00 on January 11. On January 11, the retention period of yearly backups conflicts with the retention period of monthly backups. In this case, the special retention period of monthly backups is postponed to take effect on January 12.
Weekly backups
The backup generated on Sunday, January 16 is retained for five weeks. The special retention period of weekly backups takes effect.
General backups
The other backups generated from January 11 to January 20 are retained for seven days.
Example 3: Delete special backups
At 00:00 on January 21, you delete the special backups that are generated on January 1, January 2, January 11, and January 12. The following list describes the retention periods of backups that are generated from January 21 to January 31.
Yearly backups
The backup generated on January 21 is retained for three years. The yearly backup generated on January 11 is deleted. No yearly backup exists between 00:00 on January 11 and 00:00 on January 21. In this case, the special retention period of yearly backups takes effect.
Monthly backups
The backup generated on January 22 is retained for six months. The monthly backup generated on January 12 is deleted. On January 21, the special retention period of monthly backups conflicts with the special retention period of yearly backups. No monthly backup exists between 00:00 on January 11 and 00:00 on January 22. In this case, the special retention period of monthly backups takes effect.
Weekly backups
The weekly backups generated on Sunday, January 23 and Sunday, January 30 are retained for five weeks. The special retention period of weekly backups takes effect.
General backups
The other backups generated from January 21 to January 31 are retained for seven days.
As of 00:00 on February 1, the following backups are still retained:
The yearly backup generated on January 21 is retained for three years.
The monthly backup generated on January 22 is retained for six months.
The weekly backups generated on January 3, January 9, January 16, January 23, and January 30 are retained for five weeks.
The general backups generated on January 25, January 26, January 27, January 28, January 29, and January 31 are retained for seven days.
How do I configure special retention periods?
In the Lifecycle section of the Edit Policy panel or the Create Policy panel, you can configure the Special Retention Period parameter. You can set the retention period of general backups to seven days, the retention period of weekly backups to five weeks, the retention period of monthly backups to three months, and the retention period of yearly backups to one year, as shown in the following figure. For more information, see Manage backup policies.
After the special retention periods take effect, you can find special backups in the backup timeline. For example, the following figure shows a yearly backup.
