Grandfather-Father-Son schemeAt a glance
Description Let us suppose that we want to set up a backup plan that will regularly produce a series of daily (D), weekly (W), and monthly (M) backups. Here is a natural way to do this: the following table shows a sample two-month period for such a plan.
Daily backups run every workday except Friday, which is left for weekly and monthly backups. Monthly backups run every fourth Friday, and weekly backups run on all other Fridays.
Parameters You can set up the following parameters of a Grandfather-Father-Son (GFS) scheme.
At all times, a backup is not deleted until all backups that directly depend on it become subject to deletion as well. This is why you might see a weekly or a monthly backup remain in the archive for a few days past its expected expiration date. If the schedule starts with a daily or a weekly backup, a full backup is created instead. Examples Each day of the past week, each week of the past month Let us consider a GFS backup scheme that many may find useful.
Backup scheme parameters can then be set up as follows.
As a result, an archive of daily, weekly, and monthly backups will be created. Daily backups will be available for seven days since creation. For instance, a daily backup of Sunday, January 1, will be available through next Sunday, January 8; the first weekly backup, the one of Saturday, January 7, will be stored on the system until February 7. Monthly backups will never be deleted. Limited storage If you do not want to arrange a vast amount of space to store a huge archive, you may set up a GFS scheme so as to make your backups more short-lived, at the same time ensuring that your information can be recovered in case of an accidental data loss. Suppose that you need to:
Backup scheme parameters can then be set up as follows.
With this scheme, you will have a week to recover a previous version of a damaged file from a daily backup; as well as 10-day access to weekly backups. Each monthly full backup will be available for six months since the creation date. Work schedule Suppose you are a part-time financial consultant and work in a company on Tuesdays and Thursdays. On these days, you often make changes to your financial documents, statements, and update the spreadsheets etc. on your laptop. To back up this data, you may want to:
Moreover, assume that you want to retain access to all backups, including the daily ones, for at least six months. The following GFS scheme suits such purposes:
Here, daily incremental backups will be created on Tuesdays and Thursdays, with weekly and monthly backups performed on Fridays. Note that, in order to choose Friday in the Weekly/monthly field, you need to first select it in the Back up on field. Such an archive would allow you to compare your financial documents as of the first and the last day of work, and have a five-year history of all documents, etc. No daily backups Consider a more exotic GFS scheme:
Backup is thus performed only on Fridays. This makes Friday the only choice for weekly and monthly backups, leaving no other date for daily backups. The resulting “Grandfather-Father” archive will hence consist only of weekly differential and monthly full backups. Even though it is possible to use GFS to create such an archive, the Custom scheme is more flexible in this situation. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||