Long Term Archive To Tape - 20 Years

Last post 07-15-2019, 5:13 PM by Anthony.Hodges. 6 replies.
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  • Long Term Archive To Tape - 20 Years
    Posted: 07-09-2019, 7:35 PM


    I have the following backup policy and retention periods below. I've been reading up on Deduplication-to-tape, but not sure if it can be applied to number 3 archive below. From what I read dedup to tape only applies to data on disk. If it is possible I would really like to dedup to tape for the long term archive. Currently it takes about 16 LTO5 tapes for number 3 archive.

    Is dedup to tape possible for number 3 below?

    Any suggestions if this is not possible. 


    1. Primary backup to disk. Retention 4 Weeks.

    2. Aux Copy to tape. Retention 8 Weeks.

    3. Aux Copy to tape (archive). Selective Copy, quartery fulls. Retention Long term (20) years.


    Thanks in advance.


  • Re: Long Term Archive To Tape - 20 Years
    Posted: 07-10-2019, 7:23 AM

    Hi Lance 

    Commvault does support Deduplication to Tape, this is referred as Silo Copy (https://documentation.commvault.com/commvault/v11/article?p=12481.htm)

    The purpose of SILO Copy, is to regularly seal the DDB (so the Deduped Data doesn't get too large) and Aux Copy the Dedupe Data to Tape. 

    Note - while doing restore you will need a staging area to restore the Deduped Volume, so you can then grab the required data (if you need to do granular restore)

    Hopefully this helps



  • Re: Long Term Archive To Tape - 20 Years
    Posted: 07-11-2019, 3:08 PM


    What I read and understand is the SILO copy is the Deduped Data being placed on tape, for the purpose of freeing up the storage on a magnetic library. Is this correct?


    Would I be able to Dedup to tape for Aux copy 3 in my original post? The storage in Aux copy 3 is a copy to tape.

    So If I deleted all datasets in copy number 1 and 2, I should still be able to restore from number 3? Is that correct?



  • Re: Long Term Archive To Tape - 20 Years
    Posted: 07-12-2019, 4:08 AM

    Be careful what you wish for. Laughing

    Can you ensure that your tapes will last for 20 years?

    Do you have a planned media refresh strategy to provide continuity when your tape library inevitably dies and becomes obsolete?

    Do you believe that current Commvault Deduplication will still be around and supported in 20 years?

  • Re: Long Term Archive To Tape - 20 Years
    Posted: 07-15-2019, 7:47 AM

    Hi Lance

    With configuring Silo, you will still require a Disk Storage during the restore process:

    • By default, volume folders retrieved from tape are written to the original source mount path. If the original source mount path is not available or has insufficient storage, any other mount path in the library with sufficient space will be used.
    • So if the Primary Disk Library is offline, you will need temporary Disk Storage for the staging of the Deduped data from Tape. 
    • Documentation - https://documentation.commvault.com/commvault/v11/article?p=12477.htm

    Furthermore Anthony does raise a good point, and would be good to consider alternatives (Archive Object Storage - Disk-based).



  • Re: Long Term Archive To Tape - 20 Years
    Posted: 07-15-2019, 4:11 PM

    I use a SILO copy - which is a Dedupe to tape. I have to hold records and PHI for 25+ years. I reguarlly test tapes and once every 18months cyle out oldest tapes with a fresh backup of that data to a new tape. Painstaking but i know the tapes aregood :)

  • Re: Long Term Archive To Tape - 20 Years
    Posted: 07-15-2019, 5:13 PM
    Over 20 years on tape will constantly require a technology refresh. Silo has that problem as it has entered obselence as at sp16.

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