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Thread: ZCB Upload fails, possible to restore some data?

  1. #1

    Default ZCB Upload fails, possible to restore some data?

    Hi there guys,

    Hope someone can help me out here.

    I am running some Differential backups on Zmanda Cloud Backups, but it has not completed 100% due to power failures interrupting the uploads.

    I have about 5 runs that have uploaded about 40-70% that I checked on say 10 minutes prior to the power failures.

    The drive the data was on has failed now.

    Is there any method I can try that could at least restore some of the data that uploaded from that 40-70% ?

    I tried using the restore catalog, then I just get the message "Backup run data not found".

    ****

    Ok so after getting some help from Zmanda support we managed to download some of the.DATA files using the JetS3 tool.

    I did the "copy /b *.data.* bigfile.zip" command, and when trying to unzip it, we get "cannot open as archive" using 7zip, and PKzip keeps asking for the next disk.

    Anyone maybe have any ideas on this?
    Last edited by JohanBarnard; November 14th, 2013 at 02:41 AM. Reason: Updated

  2. #2
    Join Date
    Jan 2012
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    Oklahoma
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    Default

    Hi Johan,

    I've already replied to your other email, but I'll go ahead and put a similar response here so anyone who reads the topic can see the answer!

    There really isn’t a solid answer to this question. It really depends on your setup and situation. In particular, it matters if the partial backups are encrypted or not and if the backups are locally available or only available on the cloud. It also matters for the backup type. File system backups can often be partially recovered, even from differential or incremental backups. Database backups, like MySQL and Exchange, etc, only have a chance to be recovered from full backups, and even if you can recover, it may not be importable into your database software if the file is incomplete.

    Partial backups cannot be used with Restore Catalog, as you discovered. Any recovery attempts must be made without ZCB using other tools.

    1) If you encrypt your backups, the answer is no. Data cannot be recovered from encrypted partial backup runs.

    2) If your backups are unencrypted, and the backups are available locally, the answer is “probably”.
    a. Note that “local” backups are anything not on the cloud. This includes external harddrives, NAS devices, whatever, so long as a copy of the .data file created by ZCB exists.
    b. All of our backups are packaged using PKZip’s algorithms. If you have the .data files locally, they can be opened with PKZip and extracted in most circumstances.
    i. A free demo of PKZip is available at PKZip’s website here: [url]http://www.pkware.com/software/pkzip/windows[/url]
    ii. Other ZIP tools, such as WinZIP, WinRAR, and 7Zip may or may not work, depending on the settings you used and what version of ZCB you are running.
    c. Any complete backup on local disk can, without question, be opened with PKZip so long as it is not encrypted. Partial backups can usually extract some files, can often extract most
    files, and very rarely can extract all files. It kind of depends on where the backup terminated. So don’t be surprised if some files fail extraction.

    3) If your backups are unencrypted and only available on the cloud, and you are using ZCB with Amazon S3, you might be able to extract some of the data, but it is less certain.
    a. Backups are uploaded in 10mb chunks, to enable more efficient transfer and better resume capabilities.
    b. You have to download all of the “chunks” of the backup from the cloud using a tool called jets3t (more on this below).
    c. You then have to merge the chunks into a single archive, which you then try to open with PKZip as discussed above.
    d. Please contact Zmanda support for information about the jets3t tool, how to download it, instructions on how to use it, and how to merge the chunks.

    There are no promises here, but you can usually get something from a partial file system backup.

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