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felonious_caper's avatar
felonious_caper
Level 5
12 years ago

Differential Backups

I have a dilema.   Curretly on one server we run the following backups:   1 monthly full backup - kept for a year 1 weekly full backup - kept for 6 months 1 daily differential incremental...
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  • revarooo's avatar
    revarooo
    12 years ago

    >> Is my assumption correct?  What are some ways around this? I know one would be to keep the retention period for the offsite tape at 6 months, but at that point, I'm back where I started with wasting tape.

    Couple of ways around this. When you run your weekly backup that you keep onsite (for 6 months) duplicate it to another tape (can use SLP or Vault for this), that way you can get rid of your additional weekly (that you offsite) and your backup on Monday will capture whatever has changed since that last full weekly.

    Another cruder way which I don't recommend is copy the policy and have a full backup schedule only, that way your incremental on the other policy does not check this policy/schedule backup but its own last full but the 1st method above is way way superior and easier to manage.

TomerG's avatar
TomerG
Level 6
12 years ago

I think you are approaching this from the angle of saving tapes, but maybe an approach from the expected SLAs (Service Level Agreements) is better? 

For instance, do your customers (users) expect to be able to restore a file from anytime in the day? I mean, if a user creates a file, then deletes it a few hours later, do they expect to be able to restore the data. Of course with daily backups (incremental or otherwise) you won't get this level of restore-ability. You'd need technology like continuous data protection to get that. 

So, although you are worried about some file that is lost on the Saturday morning (your original post), it could be this is just outside the scope of what you need to provide. Or if it is within the scope, then no way around it, keep the backups for that long. Or change your technology so your using something like deduplication storage to be able to manage many daily incrementals without the use of much disk space, etc.and only keep the tapes (which provide a lower level of recoverability) for long-term storage.

When it comes down to it, it should be the business defining the level or restore-ability, and your job to provide it, or if you can't: complain and ask for more money and technology to be able to provide it. I don't think there is a way around your issue without some other changes.