Forum Discussion

Zahid_Haseeb's avatar
Zahid_Haseeb
Moderator
15 years ago

Howto use Tape compression in NBU Server

Environment

NBU Server = 7

OS = win2008

 

I am using NBU Server successfully. I have a Tape Drive of HP with 4mm speed. My Tape Cartrige is 4mm with a capicity of 36GB and with compression its 72GB. 

 

  1. Do i enable the Tape compression via NBU Server (there is a check of compression in the NBU policy) ? I mean i use the Tape compression facility control via NBU compression check thru NBU Policy ?
  2. Or i have to do something other to use the Tape compression facility ? 
  3. Or i can use the NBU compression and the Tape compression simultaneously ?
7.1.x and Earlier
Backup and Recovery
NetBackup
  • Yasuhisa_Ishika's avatar
    Yasuhisa_Ishika
    15 years ago
    NetBackup can not manage drive's hardware compression function. This is managed on OS and driver level - st driver and its device file on most of Unixs, and driver's property on Windows. Check the properties of your drive's driver on Windows Device Manager whether you can set compression on or off. Considering the capacity, enabling both(NBU's software compression and drive's hardware compression) is meaningless. And it is sometimes harmful for backup throughput.
  • RiaanBadenhorst's avatar
    RiaanBadenhorst
    Level 6
    15 years ago

    Hi,

     

    You should only ever use compression at one level i.e. hardware of software layer.

     

    Tape compression should be configured by default on the tape drive. You can verify this on the drive, there might be jumper settings or switch or something. For newer drives like LTO, its on automatically.

     

    I would not recommend software (netbackup) compression as it will slow down your backups tremendously.

     

    R

  • Yasuhisa_Ishika's avatar
    Yasuhisa_Ishika
    Level 6
    15 years ago
    NetBackup can not manage drive's hardware compression function. This is managed on OS and driver level - st driver and its device file on most of Unixs, and driver's property on Windows. Check the properties of your drive's driver on Windows Device Manager whether you can set compression on or off. Considering the capacity, enabling both(NBU's software compression and drive's hardware compression) is meaningless. And it is sometimes harmful for backup throughput.
  • Joe_Despres's avatar
    Joe_Despres
    Level 6
    15 years ago

    Never use compression within NBU.....

    Someone used this by mistake....  We were backing up extremely slow!

    Backups shot up in speed after it was removed....

     

    Joe Despres

  • Zahid_Haseeb's avatar
    Zahid_Haseeb
    Moderator
    15 years ago

    Thanks all for their kind replies

     

    Yosuhisa: As you said

    """"Check the properties of your drive's driver on Windows Device Manager whether you can set compression on or off.""""

    its by default ON i saw the compression as per your suggestion

    But one problem here. I did not know that the Tape compression is by default ON and i also enabled the NBU compression from the NBU Server and i have been taking the backup :(....  

    So for the safety point view i should disable the compression from NBU Server OR should disable the compression from the Tape Drive ?? 

  • RiaanBadenhorst's avatar
    RiaanBadenhorst
    Level 6
    15 years ago

    As stated above, never use compression in NBU, its terribly slow..... Stick with the tape/hardware compression.

  • teiva-boy's avatar
    teiva-boy
    Level 6
    15 years ago

    Software compression, means that the client machines will spend extra CPU cycles to compress the data before backing it up and sending it over the LAN.

    Hardware compression, what is built into a tape drive, is done on the fly, with no impact to CPU performance.  It's near wire-speed so to speak.

     

    You should only pick one, with hardware compression being the preferred.  However, there are rare cases, where you do it on the client side.  If both were left on, the tape compression would be redundant, and would not be able to compress much more of anything, as it was already done on the client first.

     

  • Zahid_Haseeb's avatar
    Zahid_Haseeb
    Moderator
    15 years ago

    Thanks Teiva but please clear some points

     

    Would be Redundant means unused / in de-activated mode ?

     

    You mean there is no harm if both left ON thn the TAPE drive will not apply its compression because the backup already compressed by NBU Server ?