Windows 8: Thoughts on File History and the removal of Volume Shadow Copy

Discussion in 'Software for Windows' started by Wardrop, Aug 19, 2012.

  1. Wardrop

    Wardrop Member

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    As you may or may not know, Windows 8 has scrapped what I thought was one of the killer features of Windows Vista/7, which was "Previous Versions" (aka. VSS - Volume Shadow Copy Service), and have essentially replaced it with something considerably different, File History. I only found this out yesterday after installing Windows 8 and wondering where the "Previous Versions" tab had gone. Then to my horror, I stumbled across this ArsTechnica article: http://arstechnica.com/information-...tep-back-in-time-with-windows-8s-file-history

    For me, it was the straw that broke the camels back, and I promptly restored the Windows 7 image I made before installing 8. The ArsTechnica article was good because it shone a critical eye on File History as a replacement for VSS, and did well representing the perspective of the power user. The problem is that Microsoft has replaced a whole-disk in-place versioning technology with a partial off-disk backup tool. They're completed different.

    I found it bewildering that Microsoft would essentially throw VSS in the bin, after I was sure it had an even brighter future. I've always been of the opinion that with todays gigantic hard-drives, it should be impossible for a user to lose a file as a result of either their own mistake, or the fault of software. VSS was a step towards that, and as long as you had it enabled on all your storage volumes, it ensured you could never completely lose a file by doing something as easy as overwriting it. I was sure the next logical step for Microsoft would be to not only have VSS enabled by default on all volumes, but to automatically devote all free-space (or at least a large percentage of) to VSS - shadow copies would be deleted as space is consumed. After all, what use is free hard-drive space. It's the same idea as RAM. Free RAM doesn't do anything for performance, so why not populate it with cached data, which is exactly what SuperFetch did.

    Instead, Microsoft have taken a step backwards, and now we're left with big hard-drives with free space that goes completed wasted, leaving users vulnerable to losing their valuable data. What perhaps makes this worse, is that "File History" is a trivial technology that any 3rd party vendor could implement - in fact most pay-for backup solutions come with versioning functionality (sure, maybe their interface isn't as pretty, but the data is there). It's akin to replacing UAC or some other low-level security mechanism with Microsoft Defender. The obvious flaw of these backup solutions, including File History, is that they're not differential, and so keeping versions of large and frequently changing files is not practical, and here comes the part I think stings the most: 3rd parties cannot re-implement VSS. VSS is a low level feature built-into the NTFS driver; it needs to be aware of every modification made to the file system.

    So what Microsoft have done is taken a huge backwards step in regard to protecting user data. Instead of heading toward a future where losing data is a problem of the past, they've headed in a direction representative of where we were at 10+ years ago.

    With VSS, one can maintain backed up and versioned data with only double + 20% of their primary storage. If I had 8TB of data, I can maintain a complete backup of that, with weeks if not months of previous version information, on a 10TB volume. File History, depending on the size of the files you work with, could demand an exponential amount of storage to backup that 8TB of data. If you've got a few big files that change frequently, they'll eat away at the backup space available requiring older versions of smaller files to be removed, further reducing the effectiveness of the versioned backup. That's always been the problem with Time Machine on the Mac.

    At the least, Microsoft could of improved on the time machine (file history) idea by implementing reverse differential backups instead of incremental, which would come with similar storage efficiency as VSS. A reverse diff is pretty simple. For every backup, you do a diff on each file that has changed since the most recent backup; you wouldn't even have to read the whole backup file, you could derive what has changed from a checksum of each block/page/megabyte/whatever. The diff is then applied to the backed up file (to save recopying the whole file, preserving bandwidth). What you then do is store the inverse of that diff with the current backup, hence making the diff file your previous version. To load the file as it was 8 versions ago, you apply the 8 most recent reverse diff's to the current most recent backup. The computational heavy operation of rebuilding the old version is only required when you actually want to restore it, so the performance of the backup remains relatively quick. This is a much cleverer way to do backup and versioning, and would work well backing up over low bandwidth such as to the internet. The good thing about reverse diff's is that you don't need to make an initial full-copy and base your diffs off of that. Instead, your most recent backup is always your full copy, so storage efficiency is maximised. Missed opportunity Microsoft!

    I don't plan to upgrade to Windows 8 not only for this reason, but for all the other reasons why Windows 8 doesn't make any sense. I'm only praying that Microsoft realise their mistake (as they sometimes do) and bring VSS back as an even better technology package.

    Is my assessment of File History fair? I have doubts that I'm seeing the whole picture here as what Microsoft have done just doesn't seem to make any sense. If Microsoft's interpretation of keeping-up-with-the-times and staying agile is making sweeping thoughtless and poorly implemented changes, then I'm bailing.
     
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  3. theevilsharpie

    theevilsharpie Platinum Member

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    Shadow Copy sounds great in theory, but hasn't been terribly reliable in practice, especially when the snapshots are stored on the same volume as the data being snapped. In particular, there are too many situations (for example, defragmenting) which can cause a snapshot to be excessively large, which then wipes out as many older snapshots as needed to make room. I use Shadow Copy as a user-facing backup system because it's fast, but there's been far too many situations where I've had to restore a file from the main backup because the Shadow Copy snapshot it was on got wiped out for some reason. If Shadow Copy was my one and only backup system, I'd be screwed.

    I haven't used File History, but for the vast majority of home users, I think it's a step in the right direction. At the very least, it won't lull them into a false sense of security like Shadow Copy will. If you've got an edge case where File History doesn't work well, you can always use third-party backup software.
     
  4. Cerb

    Cerb Elite Member

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    Previous versions only works if it keeps previous versions, though. I've always considered it a useless tab. What do you that can guarantee you'll have prior versions? I've yet to see anything but it search and find nothing.

    Oh, OK. Yeah, don't do that :). It probably doesn't keep versions long enough...

    VSS is good current-snapshot backups, so that the system can be used during a backup. However, such a lazy snapshot system is far from ideal:
    1. A badly fragmented system can time out when trying to make a snapshot (I don't think there's a piece of accounting software isn't capable of making this happen with a HDD, unless a PC is on 24/7 to give enough time to the defragger).
    2. If the drive does not have enough free space, the snapshot might be killed before the backup job even completes.
    3. The computer slows down a great deal while creating the snapshot, and editing files in the snapshot.

    They would need to break away from NTFS to do it right.

    VSS has not been canned. That would present some serious business user outrage. Only the, "Previous Versions," tab has been canned.

    http://msdn.microsoft.com/en-us/library/windows/desktop/hh848072(v=vs.85).aspx

    I won't disagree, but you can't do that well enough using technology who's limitations are still there from the days when hard drives were small, and IOPS were precious. MS really needs to come up with a FS to truly supersede NTFS, that is feature-competitive with ZFS and BTRFS, and which will be supported by all versions of Windows.

    Except that freeing RAM is a far quicker process than freeing drive space used by files, even on SSDs.

    No, Superfetch predicted what data was likely to be used, and pushed it. RAM is populated by cached data even without it.

    Ballmer sees flows of money. The whole picture is lost on him. MS could very well have one-upped Time Machine, and could be working on a truly next-gen FS for all products (ReFS is cool, but not that cool), but they aren't and probably won't be.
     
  5. Wardrop

    Wardrop Member

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    First, you need to enable previous versions for each volume. Then, you need to schedule the task to run frequently. For me, the built-in task was unreliable, so I wrote a little vbs script to kick it off programatically every 2 hours. This guaranteed I had previous versions every two hours. I never had any of the issues you described.

    As for the rest of the points, thanks for elaborating. Maybe Microsoft's re-assessment of VSS was justified. I think it's really just File History I have a problem with. The fact that it doesn't do differential/delta backups is what lets it down. Microsoft killed VSS (sure, it may have had problems), but you can't call File History a replacement.
     
  6. Cerb

    Cerb Elite Member

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    Now, how many people are going to be doing that? Almost nobody. It's way easier to just use backup software, which does even more stuff.

    Probably never had to back up many gigs of random and/or fragmented accounting files :). VSS works, and is a great feature, but it is fragile.

    MS has a thing about keeping 3rd-party markets alive and well, until things just get really bad (Windows Defender and MSE, FI). It makes sense for them, but these sorts of things can easily show why even people outside of the RDF can like Macs. Personally, I don't see why they couldn't implement File History on the same drive, limiting it to a % of free space.
     
  7. Chiefcrowe

    Chiefcrowe Diamond Member

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    Personally i don't think this is That bad, since I tend to use other backup software.

    A new file system would be nice from microsoft though, that would have been really awesome.
    I also think that File History definitely should have reverse differential.

    I think file history on the same drive kind of defeats the purpose of backups.
     
  8. Wardrop

    Wardrop Member

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    Yeah, hardly anyone. That was a problem that could be easily fixed though if VSS was given a little love.

    When I first heard about File History, I just assumed it was an enhancement of VSS that allowed you to use another disk. Ideally, you'd want your versions to be part of your backup, and I thought File History was going to deliver this with the same space-saving smarts as VSS. Unfortunately, File History is a simplistic implementation that doesn't suit anyone who toys with larger files. Sadly, I think the market is more and more becoming consumer driven. Hardware vendors and OS developers tend to care less about power users these days, and would rather cater to the other ~80% exclusively. In the past, they'd cater for everyone. It's a shame because dumbing down the interface and technologies also dumbs down the users (or keeps them dump).

    It's just a shame that MS has a technology that no other vendor could mimick, and yet have thrown it away and opted for a solution that every vendor already implemented 10 years ago.
     
    #7 Wardrop, Aug 21, 2012
    Last edited: Aug 21, 2012
  9. Cerb

    Cerb Elite Member

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    Not only that, but it leaves out potential integration of useful features over time that normal users don't know could be useful to them; putting most effort into what big companies consider important for you to consume, instead.
     
  10. Nothinman

    Nothinman Elite Member

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    I don't particularly care how they handle it on the back-end, but removing Previous Versions and just telling you to do more backups is a huge misfeature. This also says to me that NTFS is getting long in the tooth and needs some work to compete with current filesystems that handle snapshots easily, like BTRFS and ZFS.
     
  11. zeschnoz

    zeschnoz Junior Member

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    Any idea how to re-enable the Previous Versions UI by some sort of hack since the functionality already exists? Or perhaps a 3rd party tool?
     
  12. corkyg

    corkyg Elite Member<br>Super Moderator <br>Peripherals
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    Back to the original premise - when Vista came out, followed by 7, VSS was the first thing I disabled. It took up disk space with immovable blocks that caused drive fragmentation before and after.

    I found VSS served no useful purpose for my system - I use switchable duplicate drives.

    File history could have possible value - but, right now I can't think of any reason to use it (yet!)
     
    #11 corkyg, Oct 11, 2012
    Last edited: Oct 11, 2012