Forum Discussion

Bharath_Achar's avatar
11 years ago

Is there a way to directly extract/untar backup images from tapes to client.

we used Netbackup to backup the client.

 

client is crashed now. we need to restore the enitre data drives, which is 40 TB(which is most critical data).   we need to restore them ASAP.  

Is there a way to directly extract/untar backup images from tapes to hardisk on client. or any other fast way.

 

 

  • Using the BAR GUI in Netbackup is the fastest way to get your data back.

    That being said, the command is in fact "tar" you will also need the "mt" command to navigate the tape.

    The problem you are going to run in to is that you don't know what file to extract. Files on a tape are accessed sequentially. 1 is the Netbackup header and images should start at 2 onwards but there could be multiple headers. You might have over 200 images on one tape.

    You can run through them all one by one and extract all the images but then you are going to have a mess. It also depends on what type of backups these are. Only filesystem backups are going to be recognized by tar. You can pull the data out RAW with the "dd" command. If the backup was compressed or encrypted you have a long road ahead of you.

    man tar:

    http://unixhelp.ed.ac.uk/CGI/man-cgi?tar

    man mt:

    http://linux.die.net/man/1/mt

    man dd:

    http://linux.die.net/man/1/dd

     

    and then there is a Netbackup blog about this topic:

    https://www-secure.symantec.com/connect/blogs/how-use-tar-restore-data-tape

     

    Good luck with that. I recommend just installing a Netbackup master server and using the import commands to import the tape headers in to the Netbackup catalog. Then you can quickly locate and restore your data. Much faster than hacking it out with direct hardware access commands.

6 Replies

  • Using the BAR GUI in Netbackup is the fastest way to get your data back.

    That being said, the command is in fact "tar" you will also need the "mt" command to navigate the tape.

    The problem you are going to run in to is that you don't know what file to extract. Files on a tape are accessed sequentially. 1 is the Netbackup header and images should start at 2 onwards but there could be multiple headers. You might have over 200 images on one tape.

    You can run through them all one by one and extract all the images but then you are going to have a mess. It also depends on what type of backups these are. Only filesystem backups are going to be recognized by tar. You can pull the data out RAW with the "dd" command. If the backup was compressed or encrypted you have a long road ahead of you.

    man tar:

    http://unixhelp.ed.ac.uk/CGI/man-cgi?tar

    man mt:

    http://linux.die.net/man/1/mt

    man dd:

    http://linux.die.net/man/1/dd

     

    and then there is a Netbackup blog about this topic:

    https://www-secure.symantec.com/connect/blogs/how-use-tar-restore-data-tape

     

    Good luck with that. I recommend just installing a Netbackup master server and using the import commands to import the tape headers in to the Netbackup catalog. Then you can quickly locate and restore your data. Much faster than hacking it out with direct hardware access commands.

  • Data protection is all about SLA's. If 40TB of data was only protected via tape backup, there is no magic that is going to restore faster than it was backed up. Reading tapes with tar commands is not going to restore any faster than doing it with NBU. You will spend more time trying to figure out how to and where exactly what is on tape. Just curious to know how such a large amount of data is lost when a server craches, since large data is normally stored on external arrays with built-in raid protection? So, if server craches, the data should be safe, right?
  • "Is there a way to directly extract/untar backup images from tapes to hardisk on client" >>>> Yes, its called bprestore.

  • It can be done, but for the purpose of fast restore I would make the client a media server so the data can be read directly from the tape until the disks.

    Another option I have used is to allocate the disks to a media server, restore and then move the disks to the client in question

  • Almost 3 weeks later...

    Hopefully Bharath Achar can tell us if and how he managed to restore the data?

  • Hi Marriane,

     

    No other way, we are still performing restoration using NBU BAR GUI as the data was 40 TB in size it was in DAS configuration.