Posts Tagged ‘weekly’

GFS backup scheme in Symantec Backup Exec

March 23, 2012

Grandfather-Father-Son is an industry standard backup scheme, where you have 5 daily backups, 5 weekly backups and as many monthly as you need. Symantec Backup Exec has prebuilt policy for GFS, but before going into configuring backup scheme itself, lets talk a little bit about general backup job configuration in Backup Exec.

Basic Terminology

Inside user interface you see Jobs, Policies, Selection Lists and Media Sets. First of all you need to create Selection List, which describes what you want to backup. There you select files and folders from your Windows, Unix or NDMP servers. Then you create Media Set, which is a collection of tapes with particular append and retention periods. Append period specifies how long data can be added to the same tape and retention period tells for how long data cannot be overwritten. Retention period starts form the time of last append to the tape.┬áThen you create Policy. Policy, by means of templates, defines when backup jobs are run, where backups are stored and what is the type of backup – incremental, differential or full. One policy can consist of several templates. In template you specify backup date and time, as well as target tape library.

GFS Implementation

Backup Exec has a template for GFS backup rotation scheme. Click “New policy using wizard”, choose GFS scheme and then select schedule, target backup device and media sets for daily, weekly and monthly backups. By default Backup Exec suggests the following configuration.

Three tape media sets:

  • Daily Media Set – 1 week overwrite, 1 week append
  • Weekly Media Set – 5 weeks overwrite, 5 weeks append
  • Monthly Media Set – 1 year overwrite, 1 year append

Policy with three templates:

  • Daily Backup – Monday to Friday, Incremental
  • Weekly Backup – every Friday, Full
  • Monthly Backup – first Saturday of each month, Full

Also Backup Exec automatically creates rules to resolve conflicts. For example when both Daily and Weekly backups try to run on Friday, jobs do not conflict, because weekly backups always supersede daily. Same for monthly.

I personally prefer another schedule. First of all, if you run your jobs after midnight, you will need to shift your schedules from Mon – Fri to Tue – Sat. Additionally, I run monthly backup on the first Saturday of the month. Backup Exec by default (taking into consideration my one day shift) would suggest first Sunday for the monthly backup. However, it doesn’t make much sense to have weekly on Saturday and then monthly next day on Sunday. You would just consume more space without any benefit. Also, you can schedule monthly on the last Saturday of the month, but if the last day is Thursday, for example, then you will loose four business days from your monthly backup.

After the policy is created, you need to create backup jobs using this policy by clicking on New jobs using policy. All three jobs will be created automatically according to Selection List, as well as Policy Schedule, Target, and Backup Type parameters.

I’d also recommend everyone to configure notifications. There are general Alerts properties as well as inside each job.

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