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grosstech's avatar
grosstech
Level 3
13 years ago

Large Disk Backups on Windows Clients

Hi:

   NBU environment is 7.0.1 with a mixture of clients but my interest and weakness is Windows clients.

    I have several Windows clients with large ( > 2 TB) drives which I am migrating from an LTO-3 to LTO-5 library.  The admin in the LTO-3  library used multiple policies with exclude and include files to partition the drives which say are at d:\.  I ran a intial full backup in the LTO-5 library of one of the servers and it took over 48 hours to back up the entire drive.  Nothing fancy.  I used the ALL_LOCAL_DRIVES directive and did not break apart the large volume.  I did permit multistreaming of the data but multiple jobs in parallel never started.  I then modified the Backup Selection by removing the ALL_LOCAL_DRIVES directive and expliciting inserted d:\*.  I allowed up to 5 jobs per policy and saw that over 70 threads went up with 5 running concurrently.  The backup time was reduced from over 48 to 24 hours or twice the throughput.

    I have several questions:

1)  Are there any "Best Practice" Papers which address Windows large drive backups?

2)  Are there any dangers outside of maintenance/portability of the explicit <drive_letter>:\<wild_card> directive in the Backup selection?

     I'm aware that should someone inherit the environment without documentation and the drive is replaced and a different letter is used ...

3)  Is there some way to continue to use the ALL_LOCAL_DRIVES directive and get NBU to use multiple streams for the device without the client side include and exclude lists?

4)  Is there any danger in increasing the number of jobs per policy until I saturate the ethernet network?  The bottleneck appears to be the streaming of data from the client to the media server.

The other issue which I observed during these backups is that in the Activity Monitor the jobs immediately started.  However, writing did not occur for some time.  This could take 5 hours alone.  Was it building a backup file list?  What is the criteria that NBU uses to determine whether a file needs to be backed up or not?  I have read that for Full backups it just backs up what it encounters.  If this is the case what was it doing for 5 hours before I saw the Activity Monitor update the KB Written column?  Thanks in advance to any advice or suggestions.

2 Replies

  • > 1)  Are there any "Best Practice" Papers which address Windows large drive backups?

    I'm not sure.
    I believe the admin in the LTO-3 found his best solution after long, long struggle.
    By the way, have you consider using FlachBackup? Check Snapshot Client Administrator's Guide, page 79.
    http://www.symantec.com/docs/DOC3661

    About FlashBackup
    FlashBackup is a policy type that combines the speed of raw-partition backups
    with the ability to restore individual files. The features that distinguish
    FlashBackup from other raw-partition backups and standard file system backups
    are these:
    ■ Increases backup performance as compared to standard file-ordered backup
    methods. For example, a FlashBackup of a file system completes faster than
    other types of backup in the following case:
    ■ the file system contains a large number of files
    ■ and most of the file system blocks are allocated
    ■ Individual files can be restored from raw-partition backups.
    ■ Backs up the following file systems: VxFS (Solaris, HP, Linux, AIX), ufs (Solaris),
    Online JFS (HP), and NTFS (Windows).
    See “FlashBackup restrictions” on page 80.
    ■ Supports multiple data streams, to further increase the performance of
    raw-partition backups when multiple devices are in the Backup Selections list.
    ■ For a complete list of supported platforms, snapshot methods, and data types,
    see the NetBackup 7.x Snapshot Client Compatibility document:
    http://seer.entsupport.symantec.com/docs/337052.htm

  • 2)  Are there any dangers outside of maintenance/portability of the explicit <drive_letter>:\<wild_card> directive in the Backup selection?

         I'm aware that should someone inherit the environment without documentation and the drive is replaced and a different letter is used ...

    You should leave document if you make this choice.
    And, this method depend on current folder structure. If someone rename/move/create folder, partitioning plan will become useless.