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  • ntdsutil snapsho - size and location

    Hello all, I'm new here and appreciate the community .

    I'm studying for my MCITP, and am working on 2008 AD snapshots. I'm working in a VM environment using virtualbox.

    I'm trying to figure out
    • how much space the ntdsutil snapshots take up
    • where the snapshots are stored
    • is the ntdsutil snapshot a full filesystem snapshot? How is it NOT?

    I assume the snapshots don't take up too much space, but I also assume that the longer they're kept and the more your AD changes the more space they will take up (similar to other snapshots).

    I suspected that the snapshots were kept in 'system volume information', but I looked in there and didn't see them (I mounted my virtual hard drive on my host computer and looked). There were a couple UUID-named files, but they weren't the snapshots.

    The ntdsutil snapshots ARE snapshots of the entire filesystem - at least when you browse them they list the whole filesystem, and you can copy files out of that snapshot. So - what are they? I doubt that it's a real snapshot ... is it? It isn't listed under 'previous versions' so it's not part of Microsoft's 'normal' snapshot technology/implementation (but I knew that).

    Finally, any idea why there are two UUIDs for each snapshot? I've done a bit of poking around on the web and I saw an artice writting about longhorn in RC, and the author was assuming that would be changed before full release.

    Almost forgot, my post is very closely related to another post here at petri:
    http://forums.petri.com/showthread.p...sutil+snapshot


    Thank you so much for taking the time to read my post .
    Last edited by trevort; 16th March 2010, 13:12.

  • #2
    Re: ntdsutil snapsho - size and location

    I have very little understanding about the AD Snap Shots but Daniel does mention in his article on it that it is based on VSS. If that is true, the it really is bit level. I could be wrong on this please someone let me know if I am.


    The snapshot size will vary on how much has changed with in your AD. If you have a baseline snapshot, then change a user's group membership and take another snapshot the size difference would be tiny. (*disclaimer, im a n00b*) It will only track the changes between the snapshots, which is why it isn't good for a backup solution. That is, if it works like VSS. It really only tracks the changes not the data. Try not to relate it to an archive bit and backing up a file that has that bit set. It really only keeps that change.

    I would assume that if you had one snapshot, and then didn't take another one for say 1 year or so and had done a LOT to your AD the snapshot itself woudl be rather large (or even unusable).

    Daniel says, "NTDSUTIL snapshots are not full disk snapshots, and yes, they're stored in the System Information folder." in a previous post that you linked. So that sort of answers the question of where.

    I too have been studying for my MCITP and i recall reading something about the AD Snap shots... looks like i'm not ready for the test!!

    From a previous post linking:

    http://www.petri.com/working-active-...erver-2008.htm

    Comment


    • #3
      Re: ntdsutil snapsho - size and location

      Thanks wisdum .

      As for the location - One of the reasons I posted is because when I looked, the snapshot was NOT where Daniel said it would be. Also, Daniel (and some others) have said that it's NOT a full hard drive snapshot - but when you browse the snapshot, it lists the entire drive. And, you can copy files other than AD files from the snapshot - so, what is it if it's not the entire volume?

      Comment


      • #4
        Re: ntdsutil snapsho - size and location

        Worth checking if it shows CHANGES for the entire drive or just changes for the folder with AD in it
        What happens if AD is not on the default %systemroot% location?
        Tom Jones
        MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
        PhD, MSc, FIAP, MIITT
        IT Trainer / Consultant
        Ossian Ltd
        Scotland

        ** Remember to give credit where credit is due and leave reputation points where appropriate **

        Comment


        • #5
          Re: ntdsutil snapsho - size and location

          What do you mean exactly Ossian about changes? Between what and what exactly? I'll check. For my test domain my DC just has one volume and the AD folders are in their default locations.

          Comment


          • #6
            Re: ntdsutil snapsho - size and location

            If you change another file on the C drive, does it appear in the snapshot, or is it just AD files?
            Tom Jones
            MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
            PhD, MSc, FIAP, MIITT
            IT Trainer / Consultant
            Ossian Ltd
            Scotland

            ** Remember to give credit where credit is due and leave reputation points where appropriate **

            Comment


            • #7
              Re: ntdsutil snapsho - size and location

              As a test, I made a copy of a log file I have in my c:\temp folder, then took another snapshot. So, now I have 4 snapshots - my 2 original ones (taken a couple minutes apart from each other) from about a week ago, the one I took just before making the copy today, and the one I took AFTER I made the copy.

              The snapshot 3 snapshots I have before making the copy do not contain the copy, the one I took after making the copy (of the file in c:\temp) DOES contain the copy.

              Again, in the end, I'm just investigating to see what the ntdsutil snapshots do / contain. Are they snapshots of the whole volume? It seems unlikely that they are, but they give evidence that they are. Are they reliable snapshots? I'll be Microsoft says no. So, what are they?

              Comment


              • #8
                Re: ntdsutil snapsho - size and location

                I *think* microsoft says they aren't reliable because they don't want people to use them as a backup solution. They want you to buy DPM. Just a hunch.

                Comment


                • #9
                  Re: ntdsutil snapsho - size and location

                  I made a long post but the forum timed me out before I could submit... So to try and answer your questions:

                  how much space the ntdsutil snapshots take up
                  depends on how much data is chaging, its a full volume snapshot so they get large

                  where the snapshots are stored
                  C:\System Volume Information

                  is the ntdsutil snapshot a full filesystem snapshot? How is it NOT?
                  full snapshot of the volume ntds.dit is stored on

                  Comment


                  • #10
                    Re: ntdsutil snapsho - size and location

                    Thanks Garen.

                    As for the location of the snapshot - I mounted the virtual hard drive of the VM that I was testing with, and I couldn't find the snapshot in the system volume information directory. I'll look again.

                    As for the size: I did recently check the VSS snapshot for the system volume, and saw that it had 799 MB of data. I've never done a snapshot of the system volume, so I was suprised. The only thing I can think of that would it would be referencing would be the active directory snapshots that I took. If so, that would tell me how much space they're taking up. Unfortunately, that would make the AD snapshots lumped in with other VSS snapshots, so you wouldn't really be able to tell how much space they're taking up themselves.

                    I like that MS put this capability in with 2008 - it's very cool. I wish they had better documented it. It's as if they have this good tool, but they don't trust it totally so they don't talk about it overly much.

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