The Arcserve Backup GFS (Grandfather-Father-Son) rotation scheme is based on what is standard in the mainframe and minicomputer environments. Arcserve Backup GFS offers the following advantages.
Incremental backups
On the Schedule tab of the Backup Manager, you can select to use a 5 or 7-day rotation scheme consisting of incremental or differential backups. In incremental backup jobs, the archive bit is cleared after every incremental backup job. Thus, only the files that have changed since the last incremental job are backed up again. In general, GFS rotation schemes that use incremental backup jobs require less time to perform the daily backup jobs during the week.
Differential backups
In GFS rotation schemes using differential daily backup jobs, only the files that have changed since the last full backup job are backed up. Since differential backup jobs do not clear the file archive bit, the files that were backed up in the last differential job are backed up again. Using this scheme, the backup jobs require more time to process than incremental backup jobs. However, this strategy requires less effort to restore servers and workstations because you might need less media to restore your network machines.
GFS media naming
When media is assigned to a GFS rotation media pool, Arcserve Backup automatically assigns a name to the media, then labels the media with the backup type, date, and usage. This media naming convention allows administrators to easily identify backup media. Media for GFS rotation schemes is automatically named using the following syntax:
(backup type)-(user-defined media pool prefix)-(day-of-the-week)-(date)
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Syntax |
Definition |
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Backup Type |
F-Full backup I-Incremental backup D-Differential backup W-Weekly backup M-Monthly backup |
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User-defined media pool prefix |
The name you assigned to the media pool for your GFS Rotation scheme. |
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Day of the week |
An abbreviation for the day of the week on which the job was performed. |
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Date |
The date on which the backup was performed in mm/dd/yy format. |
Based on a weekly schedule
The GFS strategy is a method of maintaining backups on a daily, weekly, and monthly basis. GFS backup schemes are based on a 7-day weekly schedule, beginning any day. A full backup is performed at least once a week. All other days, full, partial, or no backups are performed. The daily backups are the Son. The last full backup in the week (the weekly backup) is the Father. The last full backup of the month (the monthly backup) is the Grandfather.
By default, you can reuse daily media after six days. Weekly media can be overwritten after five weeks have passed since it was last written to. Monthly media are saved throughout the year. These can and should be taken off-site for storage. You can change any of these media rotation defaults to suit your particular environment.
Note: A 5-day GFS rotation scheme requires 21 media-per-year, while a seven-day scheme requires 23 media-per-year.
The primary purpose of the GFS scheme is to suggest a minimum standard and consistent interval at which to rotate and retire the media.
Selecting GFS rotation schemes
Arcserve Backup allows you to select from predefined GFS rotation schemes on the Schedule tab of the Backup Manager when you click the Use Rotation Scheme option.
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