When configuring backup options, the main thing to keep in mind is that they are actually restore points and not data backups. When restoring, we select a day to restore to, and whatever the report data looked like on that day is what we are returned to. This means, that a daily backup, actually contains the same data, that a weekly backup would contain. There is no difference in the data contained in the backup, the only difference is the date we can restore back to.
Location: "Application Settings" > "System Management" > "Backup/Restore" > "Backup Options"
Configuration File Backups and Analysis Data Backups:
For these examples, we will use January 1st 2010 as the starting point.
Each day the backup job runs, a restore point is created. With default options(above), we will keep 7 daily backups as restore points. When the job runs on the 8th day, the last restore point(January 1st) will roll off and no longer be available.
The same is true for weekly backups. Once the backup job has ran for a week (7 days) then a weekly backup is created. If a daily would have been made as well, it is not; the weekly backup takes precedent. If the backup has ran for 5 weeks, the last weekly backup will roll off (January 7th).
This happens for each time period we decide to have a backup for. A backup time period will only be available once we have ran the backup job for that length of time. We will NOT have a yearly backup available until the backup job has ran for an entire year, and the same is true for quarterly, monthly, weekly and daily.
An example set of available restore points:
A profile backup runs everyday for the entire month of January without ever being canceled or failing. Backup options are set to the defaults (specified above). Any day there is an overlap, the restore point will be listed in only one time period. We will have the following restore points available:
Daily restore points: 30th, 29th, 27th, 26th, 25th
Weekly restore points: January 7th, January 14th, January 28th (overlap with daily)
Monthly restore points: January 31st (overlap with daily)