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Understanding of Retention for Data Backups

Last post 05-19-2011, 5:20 AM by mort. 13 replies.
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  • Understanding of Retention for Data Backups
    Posted: 05-15-2011, 9:39 PM

    Hi guys,

    I know this is a noob question but I would like to get a better understanding of Retention period on the data backup. The training that I had didn't help at all, wouldn't 100% blame the instructor, as working with CommVault more and more, there seems to be endless questions that pops up after.

     

    Basic Retention Rules for All Backups

    Basic Retention Rules for Data/Compliance Archiver Data

    Extended Retention Rules for Full Backups

     

    The above are the options to be configured when creating a SP. We had consultants coming in to set up a couple and they have selected Basic Retention Rule for All Backups to 7 Days 0 Cycles. However on Basic Retention Rules for Data / Compliance Archiver Data is set to Infinite. This has cause a pop up message to say "You have selected a different retention period for Archiver data [Infinite] compare to Regular Data [7 Days]. It is recommended to create a separate storage policy for Archiver if there is a different retention requirement. Do you wish to continue?"

     

    I have tried reading documentation.commvault.com but I can't fully grasp what exactly they mean for each options. Can someone be so kind to have a short chat with me to get a deep understanding of this?

     

    Thanks in advance,

    Jason

  • Re: Understanding of Retention for Data Backups
    Posted: 05-16-2011, 10:40 AM

    Basic Retention Rules for All Backups

    This should be the point were you would set your "normal" retention for your backups. BTW, I would not recomend setting cycles to zero.

    Basic Retention Rules for Data/Compliance Archiver Data

    CommVault (as a general desgin rule) will try to limit the use of storage ressources. Therefor, it is possible, to have "normal" Backup data and Archiver Data going to the same storage policie.

    If you do that, this popup tries to remind you, that you should not set different retention periods for the two Basic Retention Rules. Why? Because if you do so, data will not age off in a linear fashion.

    For tapes because if those backups would be going direct to tape, the tapes would age off only partially. For Disk because the data retention for archiving are normaly longer (years to infinite) and would cause the disk to overflow.

    Extended Retention Rules for Full Backups

    Typically used for stand alone drives or stackers. It should save some tapes. In my opinion you shouldn't use those settings in a "normal" environment (D2D2T with a tape library), because management is difficult. Better to use separate selective copys.

    Best Regards

    Bernd


  • Re: Understanding of Retention for Data Backups
    Posted: 05-18-2011, 3:46 AM

    Hi Jason,

    Extended Retention Rules for Full Backups

    We use this at most of our customers for rentention of weekly, monthly and yearly fulls. it works perfect. For special backups we use an extra selective copy if neccesairy. We always use this option with tape libraries.

     

    the normal use is

    weekly 27 days

    monthly 364 days

    yearly is infinit

    Further on I agree with Bernd.

    Regards Cees

  • Re: Understanding of Retention for Data Backups
    Posted: 05-18-2011, 9:13 PM

    Thanks Bernd and Cees,

    I am really having a hard time understanding this. We are using the D2D2T scenario. Currently have three copies running on a SP.

    First one being the Primary set to
    Basic Retention Rule for All Backups: 7 days 0 cycles 
    Basic Retention Rules for Data / Compliance Archiver Data: Infinite
    Extended Retention Rules for Full Backups : Nothing is ticked.

    Second a Synchronous copy to Tape
    Basic Retention Rule for All Backups: 15 days 2 cycles 
    Basic Retention Rules for Data / Compliance Archiver Data: 365 days
    Extended Retention Rules for Full Backups : For 365 Days Weekly Full.

    Third would be Selective,
    Basic Retention Rule for All Backups: 15 days 2 cycles 
    Basic Retention Rules for Data / Compliance Archiver Data: 365 days
    Extended Retention Rules for Full Backups : For Infinite  Monthly Full.

    I get the part of Extended Retention Rules where it apply itself to the Full Backups so we can keep the Synchronous copy for a year (365 days) and Selective Copy to be archived permanently.

     

    I still fail to understand what Basic Retention Rules for Data /Compliance Archiver Data is for. We are trying to archive this scenario:

    Have data on disk for 7 days (would like to extend this to 30 days) and also get a copy to tape (hence the Synchronous copy) so we can still restore data older than 7 days from the tape instead. Weekly Full Backups are stored for a year offsite and Monthly Full for infinity.

     

    Thanks again in advance,

    Jason

     

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 1:45 AM

    Hi Jason,

    What are you trying to archive?

    Do you have mail or data archiving installed?

    Regards

    Cees

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 1:53 AM

    Hi Cees,

    No archiving installed yet. We will be having that "soon".

     

    Regards,

    Jason

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 2:03 AM

    Hi Jason,

    Please create a seperate Storage Policy for archiving. So you cannot mixup backup and archiving.

    CommVault does not make a difference between archiving an backup. It works the same way.

    After the archive job is ready make an aux-copy and do a selective copy every week or month what you wish.

    Regards

    Cees

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 2:24 AM

    Hi Cees,

    We do not have archiving. I still do not understand the options on the Retention tab.

     

    Regards,

    Jason

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 2:33 AM

    Hi Jason,

    Do you know what archiving in CommVault does?

    If you know archiving than you will understand the archive option in the Retention tab.

    Please let me know.

    Regards

    Cees

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 2:47 AM

    Hi Cees,

    I do to some extend what CommVault does with archiving, but I would say it is just a glancing knowledge of it.

    From what I understand (please do correct me), CommVault creates a link and have the data store somewhere else so it does not fill up the MagLib for example.

     

    Regards,

    Jason

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 2:57 AM

    Hi Jason,

    The primary purpose of a migration archiving operation is to move data from primary storage to secondary storage, in order to free up primary storage space and to reduce the amount of data that is backed up. Significant cost savings can be realized by not storing infrequently used data on primary storage, and by minimizing the time it takes to perform backups. Also, archived data can be easily recovered when it is needed, from either the CommCell Console or through the use of a third-party application.

    So archived data is not backuped every day. After you run an archive job you must make an aux-copy to tape. In the extended retention options you can set the retention for archiving on infinit because you will keep the data for ever. After that you can make a auxcopy with different retentions.

    Hope it is clear now, if not let me know

    Regards

    Cees

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 3:35 AM

    Hi Cees,

    I have to thank you first for being so patient with me.

    Yeah I do understand the archiving part.

     

    I'm assuming that, if I do not have archiving with CommVault now. The settings on Basic Retention Rules for Data/Compliance Archiver Data will be ignored?

    If that is the case, it does not care what I set it to be, whether it is infinite or the same, in my case it is only looking at the Basic Retention for all Backups?

    Regards,

    Jason

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 3:41 AM

    Hi Jason,

    you are right.

    Good luck.

    Regards

    Cees

  • Re: Understanding of Retention for Data Backups
    Posted: 05-19-2011, 5:20 AM

    Basic Retention Rules for Data/Compliance Archiver Data

    Essentially this option is only relevant if you are sending archive jobs (therefore archive data) to the storage policy, if you are not I would suggest you simply set it to the same as Basic.

    As has already been said, when/if you start to archive data it's a good idea to use a different storage policy, you don't however have to.  You can send both backup and archive data to the same storage policy, so this simply allows you to set different retention periods for backup data and archive data should you so wish.

    The extended retention rules allow you to specify a deifferent retention period for specific conditions, consider the following:-

    A site performs full backups every Monday-Friday, they have 5 tapes labelled Monday to Friday, these will be overwritten every week so basic retention would be say, 6 days / 2 Cycles, so data will only age after 6 days providing there has been 2 good full backups during that period, a setting of zero cycles would mean the tapes will ALWAYS be overwritten after 6 days, so you could end up in a situation where backups are failing and tapes have all been partially overwritten, so you have no good copies of data, a setting of 6 cycles would mean there would need to be 6 good copies which could never happen as there is only 5 tapes, so data wouldn't age.

    Let's say they decide to get 12 additional tapes labelled Jan/Feb/Mar/.....Nov/Dec. these are put in on the first Monday of Every Month, Extended retention rules allow you to specify that these tapes should have a retention of 364 days, without affecting the standard Mon-Fri retention.

    In order to get familiar with CommVaults retention rules, I used a test setup to play with storage policy retention and ran reports to look at the state of the media, once you see the effects of the changes you make it really helps you to understand the rules.

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