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How does the WHS backup to external HD feature wrok? (Help does not give much info) RRS feed

  • Question

  • I see that it replaces only the files that have changed. If a file was erased from my server will it be erased from my external hard drive? To be safer would'nt I just want to manually transfer Shared folders to the drive that way I maintain something that may have been deleted?
    Tuesday, April 21, 2009 1:58 AM

Answers

  • This page explains how NTFS hard links work. You will need to read it to understand how the server backup feature works. Note: there are other documents, including a number on the Microsoft site, that all explain this. This link just happens to be the number one search result on Google for ntfs hard links. The number two result is a page on the Microsoft Technet site...

    The answer to your original question "If a file was erased from my server will it be erased from my external hard drive?" is (still) no. As long as at least one backup that contains that file is still on the drive, the file itself is.

    The answer to your question "SO it would be as if I copied them over manually?" is also (still) no. Copying a file from one disk drive to another will not create a hard link. It will create a second (third, fourth, etc.) copy of the file even if they are all byte-for-byte identical. Hard links, wherever they are, all point to a single entry in the Master File Table for a drive, which points to where data for the file itself can be found. If there are any hard links, only when all are deleted can the file itself (the data) be deleted. There are utilities that can be used to create a hard link instead of an additional copy of a file, but just copying a file (or using xcopy, or teracopy, etc.) will create multiple copies.

    If these are not questions you're really trying to get an answer for, please state the actual question you need answered clearly and succinctly, because we've answered the questions you've asked so far (they have unequivocal, factual answers, and are not matters of opinion) and those answers don't seem to satisfy you.

    I'm not on the WHS team, I just post a lot. :)
    Friday, April 24, 2009 9:47 PM
    Moderator
  • Sounds like synctoy might be what you're looking for, jshoe.  Or robocopy seems to have a bit of support around here as well.
    Saturday, April 25, 2009 1:52 PM

All replies

  • The Server Backup feature uses NTFS hard links, which are similar to pointers, to make it look like every backup contains all the files on the server at that time. So no, when you delete a file from your server it won't be deleted from the backup disk until you delete every backup that contains that file.
    I'm not on the WHS team, I just post a lot. :)
    Tuesday, April 21, 2009 4:26 AM
    Moderator
  • So will the files be stored as a single BKF file or will they be stored in a 'normal' folder structure? Thanks
    Thursday, April 23, 2009 1:21 AM
  • So will the files be stored as a single BKF file or will they be stored in a 'normal' folder structure? Thanks
    It uses multiple folders, not a BKF file.
    Thursday, April 23, 2009 1:46 AM
    Moderator
  • SO it would be as if I copied them over manually?
    Friday, April 24, 2009 4:28 PM
  • No. If you copy them manually, you will have e.g. 4 copies of a file, all identical, if you "back up" your server shares manually 4 times and that file doesn't change. The way the Server Backup feature works, you have one copy of the file, with 4 "pointers" to it. If/when all pointers are deleted from the disk, the file will be as well.
    I'm not on the WHS team, I just post a lot. :)
    Friday, April 24, 2009 7:07 PM
    Moderator
  • If I manually copy and replace the files I will have only one copy and nothing will be deleted. So if I'm worried about things being deleted and want to have a good backup with all files, even files deleted from the server I should not use the backup feature? I mean if this were at an office I'd have archived tapes but this isn't the case. I want to make sure nothing gets deleted accidently or maliciously. Thanks
    Friday, April 24, 2009 9:03 PM
  • This page explains how NTFS hard links work. You will need to read it to understand how the server backup feature works. Note: there are other documents, including a number on the Microsoft site, that all explain this. This link just happens to be the number one search result on Google for ntfs hard links. The number two result is a page on the Microsoft Technet site...

    The answer to your original question "If a file was erased from my server will it be erased from my external hard drive?" is (still) no. As long as at least one backup that contains that file is still on the drive, the file itself is.

    The answer to your question "SO it would be as if I copied them over manually?" is also (still) no. Copying a file from one disk drive to another will not create a hard link. It will create a second (third, fourth, etc.) copy of the file even if they are all byte-for-byte identical. Hard links, wherever they are, all point to a single entry in the Master File Table for a drive, which points to where data for the file itself can be found. If there are any hard links, only when all are deleted can the file itself (the data) be deleted. There are utilities that can be used to create a hard link instead of an additional copy of a file, but just copying a file (or using xcopy, or teracopy, etc.) will create multiple copies.

    If these are not questions you're really trying to get an answer for, please state the actual question you need answered clearly and succinctly, because we've answered the questions you've asked so far (they have unequivocal, factual answers, and are not matters of opinion) and those answers don't seem to satisfy you.

    I'm not on the WHS team, I just post a lot. :)
    Friday, April 24, 2009 9:47 PM
    Moderator
  • I'm sorry to have bothered you. I just wanted to see how a WHS backup was compared to a Server 2003 backup.
    Saturday, April 25, 2009 3:49 AM
  • Sounds like synctoy might be what you're looking for, jshoe.  Or robocopy seems to have a bit of support around here as well.
    Saturday, April 25, 2009 1:52 PM
  • Synctoy would make sense. Thanks
    Saturday, April 25, 2009 1:53 PM