XPost: alt.comp.os.windows-10, alt.comp.microsoft.windows   
   From: mariasophia@comprehension.com   
      
   Paul wrote:   
   > vssadmin list shadowstorage   
   > vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool   
   > (C) Copyright 2001-2013 Microsoft Corp.   
   >   
   > Shadow Copy Storage association   
   >    For volume: (C:)\\?\Volume{0bd6166a-0836-4041-891c-792df2c72abd}\   
   >    Shadow Copy Storage volume: (C:)\\?\Volume{0bd6166a-0836-40   
   1-891c-792df2c72abd}\   
   >    Used Shadow Copy Storage space: 0 bytes (0%)   
   >    Allocated Shadow Copy Storage space: 0 bytes (0%)   
   >    Maximum Shadow Copy Storage space: 2.37 GB (2%)    <===   
   >   
   > Shadow Copy Storage association   
   >    For volume: (H:)\\?\Volume{bd4d69bc-6fbb-4f12-b804-f32c6b9e828c}\   
   >    Shadow Copy Storage volume: (H:)\\?\Volume{bd4d69bc-6fbb-4f   
   2-b804-f32c6b9e828c}\   
   >    Used Shadow Copy Storage space: 29.8 MB (0%)   
   >    Allocated Shadow Copy Storage space: 320 MB (0%)   
   >    Maximum Shadow Copy Storage space: 6.45 GB (5%)    <===   
   >   
   > I can see no contribution from File History to VSS, one way or another.   
      
   Hi Paul,   
      
   Wow. That was refreshing! It's exciting to learn from a Usenet response!   
      
   Thanks for posting your numbers as we can all work together as a well-honed   
   team given each of our setups have been modified over many years.   
      
   What you're showing above is actually the "normal" case, AFAICT, and it   
   helps confirm the point of the PSA for a properly set up Windows box.   
      
   Your C: drive has a maximum shadow storage size of 2.37 GB (about 2%).   
   Your H: drive has a maximum of 6.45 GB (about 5%).   
      
   Since VSS always reports the maximum shadow storage size as a percentage of   
   the drive it's associated with, not a percentage of used space, free space,   
   or anything else, your "2.37 GB (2%)" means, I think, that your C: drive is   
   roughly 118 GB in total size and your "6.45 GB (5%)" on H: means that H:   
   drive is roughly 129 GB in total size (AFAICT).   
      
   Both of those sets of numbers appear to me to be sane, bounded values.   
   They likely won't run away and consume either of your entire disks.   
      
   In my case, the "Maximum Shadow Copy Storage space" was set to 100% of the   
   drive. I don't know why. I don't know how. I didn't even know to look.   
      
   Now I do know how to look, which is the main point of this helpful PSA:   
    C:\> vssadmin list shadowstorage /for=C:   
      
   The output doesn't mean VSS was using what it reports, but only that   
   Windows was allowed to reserve that much if it wanted to. Once the disk got   
   tight, VSS and NTFS metadata allocation pushed right up against that limit   
   and the last few GB vanished instantly, while I was editing a text file.   
      
   Your output on a better-set-up PC shows the opposite situation than mine.   
   Your max size is capped, so even if VSS wanted more space, it can't exceed   
   those limits on your machine so you won't likely see the same behavior.   
      
   Your additional helpful note about File History is apropos for this PSA.]   
      
   Looking it up, apparently Windows File History uses its own storage   
   mechanism & hence, it doesn't contribute to VSS usage. The two systems are   
   separate. I didn't realize it existed until you pointed it out. Thanks.   
    Win+R > FileHistory   
    Reported:   
     a. No file history was found   
     b. File History is currently turned off.   
     c. Configure File History settings'   
     d. Control Panel\All Control Panel Items\File History   
      
   It's probably important to note that it seems, after looking it up, that   
   File History does not use VSS shadow storage as it uses a normal folder   
   structure on whatever drive we selected as the File History target.   
    :\FileHistory\\\Data\   
      
   I'm not exactly sure what FileHistory is useful for, but it seems to be a   
   lightweight, automatic backup system for our personal files.   
    a. It's apparently not the whole system   
    b. Nor the installed programs   
    c. And certainly not the Windows installation itself   
    d. But... it seems to know what is your "user data"   
      
   In fact, it seems to be kind of sort of a set of versioned copies of our   
   Documents, Pictures, Desktop, etc., stored on another drive. Is it?   
     i. C:\Users\\Documents   
    ii. C:\Users\\Pictures   
   iii. C:\Users\\Desktop   
    iv. C:\Users\\Music   
     v. C:\Users\\Videos   
    vi. C:\Users\\Favorites   
   vii. C:\Users\\AppData\Local\Microsoft\Windows\Libraries   
      
   I don't use the official folders in C:\Users so my data will all be stored   
   on C:\data\{my folder hierarchy that makes sense to me over the decades}   
   So FileHistory won't back them up unless I add those folders to a library.   
      
   Good to know.   
   Thanks for adding topical helpful value to this PSA about shadow copies.   
      
   It keeps older versions too, so we can apparently restore yesterday's copy   
   of a file we accidentally overwrote. It seems nice. If we have the space.   
      
   In addition to your helpful information about VSS and File History,   
   that Acronis quote you found lines up with what I ran into. Some Windows   
   updates in the past (Creators Update era, Windows 8 era, etc.) were known   
   to reset the shadow storage maximum to very large values, sometimes 100%.   
      
   If that happened years ago and nobody noticed, the system would run fine   
   until the disk finally got tight, and then the problem would appear   
   suddenly. Certainly my system dates to 2009 so it has had many updates.   
      
   So your numbers look good. Mine were simply misconfigured, probably from   
   something long ago. The PSA is just to help people check that setting in   
   case they hit the same failure mode.   
      
   Thanks again for the data point as it's wonderfully exciting to communicate   
   with people who want to add helpful value so as to benefit all who read it.   
   --   
   We're each here to learn and help others & to ask for help when needed.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)