BackupWhen

Backup When Page Overview

This page allows you to control how many backup runs should be performed in a given time period, and when backup runs should be scheduled.

It allows you to specify the maximum interval between two full backups (referred to as the backup cycle), in either days or months. It calculates how many backups can be completed given the backup cycle and the days and times you have identified as the backup window (See the Days/Times panel description below). This "runspercycle" value is computed conservatively: at least one full backup is performed for each object in the backup cycle no matter what. You might find that Amanda schedules more full backups in the backup cycle than required in some cases.

More information about runspercycle parameter can be found in amanda.conf(5) man page.

You should examine the Backup When page before activating a backup set; simply visiting the page sets the Backup When options to the displayed defaults for the current backup set, which may or may not be appropriate for your site.

Backup When Page Options

The Backup When page lets you control how backups will be scheduled. You can specify the overall backup cycle time, as well as the days, dates, and times within the backup cycle when backups will execute.

• The Backup When page is divided into two panels shown below.

[need screenshot that includes "Maximum Media per Backup"]

Backup Cycle Panel

A Full Backup Cycle is the maximum time within which at least one full backup of each DLE in the backup set must happen. Amanda tries to perform full backups of the DLE as many times as possible within the backup cycle to reduce the backup recovery time. You can specify Full Backup Cycle in either days or in months.

Time Range

Select Days or Months from the dropdown for specifying the Full Backup Cycle. The GUI initially displays the default Time Range value as Days. After the Month option is selected, the ZMC right panel changes to reflect that choice.

Backup Cycle

The number of days or months within which at least one full backup for all DLEs must be performed.

Backup Time

Specifies the time of day when the backup run starts, in 24-hour format (1:00 pm is specified as 1300). This time is the same for all days and for all the DLEs in the set.

Media in rotation

Specifies the number of backup media (i.e. tapes, virtual tapes, etc.) in rotation for a backup cycle, which indirectly defines a backup retention policy. The retention policy is in relation to backup cycles rather than a specific number of days/weeks/months.

Backup media may be overwritten after the value specified is used. For example: Suppose you want to retain backup images for 7 days, and the number of media volumes per run is 2, and you are performing daily backups. The bare minimum media in rotation would be 14 (i.e., 7 times 2), but this leaves no margin of error. To account for media failures and estimation errors, Zmanda recommends that you add enough media for at least one additional backup run per cycle to this formula: (7+1)*2, i.e., 16 media in rotation). It is up to the administrator to ensure that enough labeled media is always available for Amanda to complete a backup cycle. The backup set should also have an adequate Maximum Media per Backup value set (see below).

Determining how much media is required for a run can be an iterative process. First, determine the approximate size of all the backup objects in the backup set. Assume that Amanda balanced backups will reduce the backup image size to about 70% of the original size, and set the number of media accordingly. After a few backup runs, monitor media usage using the Report->Media page and adjust the number of media accordingly.

Maximum Media per Backup

Specifies the maximum amount of media that Amanda will be allowed to consume in a single backup run. This value, coupled with Media in Rotation above, effectively sets the data retention policy for the backups.

Backup Week/Month Panel

The panel on the right (titled Backup Week or Backup Month depending on context) lets you set which days of the week or days of the month to run backups.

• When choosing a calender month, and a date such as the 31st does not exist, no back up will run on that day. It will, however, run in those months that the date is valid.

Example 1 Week(Days):+
Suppose Mondays and Fridays are heavy work schedule days on which days the user does not want any Backup to run.
Then tick Tuesday, Wednesday, Thursday, Saturday and Sunday.
If the user has specified a 10 day Backup cycle, and the user is starting the process on a Monday, no backup will happen that day. 
Full/ incremental backups will happen on Tuesdays, Wednesdays, Thursdays, Saturdays and Sundays. 
This will repeat for the entire cycle.
Example 2(Dates of)Month:
For another backup set, where User has selected slowly changing data, User has specified a 3 month Backup Cycle.   
The User wants the backups to run on the 1st, 10th and 20th of each month irrespective of what day of the week they fall on.
Just tick the dates 1st, 10th and 20th in the Month panel.

Note: On Solaris 10 servers, choosing all days of the week does not work from the Zmanda Management Console. The crontab entry on the Solaris 10 server must be changed manually. Change the crontab entry for amdump from 1-7 to 0-6 on the Amanda server on Solaris

Save

Click the Save button to save all changes before moving to the next page. If all the parameters have been entered correctly, following message is displayed:

Scheduling parameters have been saved for this backup set.