Question about LTO compression

Hi,
 In some cases  I find that an unexpectedly small amount of data is written to LTO tapes, just a little more than it should be able to contain without compression.
Is there a way to check how much data on LTO tapes is compressed in Data Protector ?

Parents
  • Hello,

    Looking at your query - Is there a way to check how much data on LTO tapes is compressed in Data Protector ?

    I guess it should be "what are the ways to check how much data on LTO tapes is compressed on a DP backup".

    I may suggest that you log a DP SUPPORT CASE as this may need deep investigation - first would be to check how things are configured - HW OS   APPLICATION (DP side).

    Same as what was mentioned in one of the reply - this depends on a lot of factors.

    I would recommend to check the HW first - LTO Library/drives, and then determine the objects (files) you are backing-up.

     

    Hope this helps

    rgds,

    Sherman

    HPE DP SUPPORT

     

  • Hello,

    The support centre can't check from a distance your infrastructure. You can't expect them to drill down into your SAN zoning f.i. just to make my point.

    LTT is prob ably the simpliest to test/check your compression ratio.

    If you'd like to see it from a DP point of view; simple:

    make a backup of a know amount of data

    what's written on tape

    restore your data (preferably somewhere else)

    compare initial in- and final out-put

    compile now your personal compression formula :-)

    Luc

Reply
  • Hello,

    The support centre can't check from a distance your infrastructure. You can't expect them to drill down into your SAN zoning f.i. just to make my point.

    LTT is prob ably the simpliest to test/check your compression ratio.

    If you'd like to see it from a DP point of view; simple:

    make a backup of a know amount of data

    what's written on tape

    restore your data (preferably somewhere else)

    compare initial in- and final out-put

    compile now your personal compression formula :-)

    Luc

Children
  • Hello,

    Yes - I am not looking at the whole infrastructure, such as the SAN zoning configuration.

    What I mean by HW is information on the tape library/drives. What I mean by OS is what files is being backed-up.

    And YES, I would concentrate more on the DP side - I need to check what is the device configuration (omnidownload) and the backup specification.

    I need to check things first before recommending any "test backup". And any test backup will be dependent on what cu have.

    Rgds,

    Sherman

    HPE DP Support