none
tape library sizing RRS feed

  • Question

  • hi,

    We are testing dpm 2010 at the moment and i would like some thoughts on long term protection to tape sizing.

    We are doing short term protection to disk for 30 days and this is using 55TB of disk space in DPM. We want to do long term protection to tape for 1 year so we are looking to buy a tape library to handle this but i'm not sure how i size it.

    I have read through some documentation and looked on forums but i havent found the answer as yet.

    Whats the ratio i should be looking at?

    Are just the recovery points sent to tape?

    any thoughts would be greatly appreciated.

    thanks

    Neil

    • Moved by MarcReynolds Monday, February 6, 2012 4:57 PM (From:Data Protection Manager)
    Monday, February 6, 2012 9:27 AM

Answers

  • Hi,

    Depending on the data being protected, the average compression ratio is 2:1 and if you look at Ultrium website - http://www.lto.org/technology/generations.html, LTO-5 has a capacity of 3TB using compression.   DPM will backup only the used space on the replica volumes, so make a disk utilization report and see what the total used space is for all the replica volumes.   All long term backups are FULL backups, we don't do incremental for long term protection, so depending on the frequency of the backups (monthly) you can plan on how many tapes you need for 1 year protection. 

    Total used replica space = 30TB
    12 - Monthly backups.

    Means you need a minimum of 120 tapes assuming 2:1 compression and the amount of protected data stays the same. 


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Tuesday, February 7, 2012 4:31 AM
    Moderator

All replies

  • Hi,

    Depending on the data being protected, the average compression ratio is 2:1 and if you look at Ultrium website - http://www.lto.org/technology/generations.html, LTO-5 has a capacity of 3TB using compression.   DPM will backup only the used space on the replica volumes, so make a disk utilization report and see what the total used space is for all the replica volumes.   All long term backups are FULL backups, we don't do incremental for long term protection, so depending on the frequency of the backups (monthly) you can plan on how many tapes you need for 1 year protection. 

    Total used replica space = 30TB
    12 - Monthly backups.

    Means you need a minimum of 120 tapes assuming 2:1 compression and the amount of protected data stays the same. 


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Tuesday, February 7, 2012 4:31 AM
    Moderator
  • Thanks for the information Mike. - Much appreciated

    Neil

    Tuesday, February 7, 2012 6:30 AM