Forum Discussion

AlGon's avatar
AlGon
Level 6
13 years ago

checkpoint restart process

 

Hi everyone,

 

Netbackup 7.1.0.2 Windows 2003 Server

 

Can someone clarify this for me please.

 

How does Netbackup restart a job from a checkpoint if the job fails?  Does it rely on the the VSS snapshot in any way or it this completely separate from checkpoint restart process.

 

Many thanks

7.1.x and Earlier
Backup and Recovery
Basics
NetBackup
  • Mark_Solutions's avatar
    Mark_Solutions
    13 years ago

    NetBackup works through a file system in a logical order when it backs it up (like going from A to Z)

    When you use checkpoint re-start it makes a not of where it has got to at each checkpoint interval so that it has a record of that.

    If it fails for any reason it can then kick back off from its last checkpoint

    So if it would check point at D, H, L, Q etc, and if it then failed when it got S it would re-start from Q as that was its last checkpoint.

    The last fragement of the image it had written from Q to S would be scrapped and re-written when it re-tried.

    Very simplified overview but hopefully this gives you the basis of the idea behind it

  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    13 years ago

    NetBackup works through a file system in a logical order when it backs it up (like going from A to Z)

    When you use checkpoint re-start it makes a not of where it has got to at each checkpoint interval so that it has a record of that.

    If it fails for any reason it can then kick back off from its last checkpoint

    So if it would check point at D, H, L, Q etc, and if it then failed when it got S it would re-start from Q as that was its last checkpoint.

    The last fragement of the image it had written from Q to S would be scrapped and re-written when it re-tried.

    Very simplified overview but hopefully this gives you the basis of the idea behind it

  • AlGon's avatar
    AlGon
    Level 6
    13 years ago

    Yes, that's really helpful, thanks Mark.  Does it keep a record of where it's got too in a log somewhere?

    I just wanted to make sure that if there are problems with the snapshot during the backup that it's not going to effect the checkpoint restart location.

  • Yogesh9881's avatar
    Yogesh9881
    Level 6
    13 years ago

    it is always good to set checkpoint if you are backing up large amount of data with big backup window.

     

  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    13 years ago

    It wont start the checkpoint until it starts wrting "files"

    It is also not available for all types of backups (It cannot do SQL, Exchange etc.)

    The System State / Shadow Copy Components are also not checkpointed as they must always be a full and valid backup - that is why an Incremental of them as always actually a full.

    This describes a few useful things to note: http://www.symantec.com/docs/HOWTO34475

    Not sure off the top of my head if the checkpoints go in the tryfile logs (netbackup\db\jobs\) or if it just uses the catalog itself