The case of the disappearing disk space
By Simon Bisson & Mary Branscombe in Editorial
Posted in Windows Vista, Storage, Laptop, HP, Microsoft on
Where has 32GB of disk space gone and how do I make Vista give it back, or there’s no such thing as a free lunch.
When we’re on the road at conferences I take a fair few photographs, and I copy a lot of PowerPoints and PDFs onto my notebook, not to mention photographing products I’m reviewing, and then there’s recordings of interviews… It all takes up space, so when I got an 8 megapixel camera the day we drove into Death Valley I did wonder if disk space on my notebook might be a problem.
Over the last few weeks I’ve been kicking along with only a few gigabytes of my 84GB disk free. Simon, who has the same laptop and takes just as many photos, had already removed the recovery partition to get 8GB back. And last week at TechEd I got down to just 1GB free,. I grabbed the biggest USB stick I have, which at 32GB is a sizable proportion of my hard drive space, and started looking for files to move, using the excellent WinDirStat to see a treemap and size-sorted folder list. Recordings and photos were the obvious place to start and after I transferred a few gigabytes of those I had enough room to download more PowerPoints and worry later. The figures didn’t seem quite right, but I was spending more time thinking about how soon we could move the server to Windows Server 2008 to get faster network file copying with SMB 2: I want to know if the 30-40x Microsoft is claiming will work for us.
Yesterday I sat down to copy the photos and recordings still on my tablet PC onto the server and after removing 3GB of recordings I had - about the same space I’d started with. I’d get up to 2.2GB and then go back down to 1.9GB or right back to 800MB free. I ran disk cleanup and deleted two 500MB files of crash reports that were hanging around waiting to upload, and felt I was rearranging deck chairs on the Titanic. I ran WinDirStat and wondered why Windows needs 13GB of disk space, 6GB of which is in the WinSxS directory - ’side by side’ versions of files to avoid DLL hell. I kept coming back to the 8GB of photos that I wanted to keep on my notebook, the 11GB I use for OneNote and Outlook caches (recordings and attachments again), the fact that the conference files I was worrying about where only 2GB because the XML PowerPoint format is so compact… and finally I looked at the summary at the top of WinDirStat that was telling me I only had 46GB of files on my hard drive.
Oh no, I thought; finally an application I care about that doesn’t run properly under Vista. Maybe every folder is just bigger. WinDirStat says it’s 20.9GB for the Users folder tree but Explorer says- well Explorer said 20.9GB as well. It’s not the swap and hibernation files; I can see 3GB for each of them in WinDirStat and besides, 84.2GB-46.5GB is some 32GB of disk space that’s missing. I cleared everything except the last system restore point: no difference. If I had 32GB of bad sectors, the hard drive ought to have raised the white flag in surrender by now. Where else would Vista be hiding disk space?
There’s a great new feature that Apple put into the Leopard release of Mac OS X called Time Machine, that takes a copy of all your files as you edit them, creating continuous backup so you can find files you’ve deleted and undo changes you made long after you’ve saved a document and moved on. Apart from the starry backdrop and the timeline scrollbar this is exactly the same as the Volume Shadow copy that Microsoft put into Windows Server 2003, which powers the Previous Versions feature in Vista, as well as System Restore. Shadow because you have to copy the ’shadow’ a file casts if it’s open or you can’t copy it at all, volume because it can get any or all files on that drive and Volume Shadow because, let’s face it, Microsoft has no clue about good product and feature names.
The interface is much less sexy too; you right-click on a file or folder and choose Restore previous versions. And how do you see how much space this really useful feature is using?
First you have to open a command prompt as an administrator; I run as a standard user because I don’t mind clicking on a dialog that confirms it’s me and not a virus mucking with the internals of Windows, so I hit the Start button, type CMD and right-click on the Command Prompt icon that appears to choose Run as Admin. The command for working with Volume Shadow Services is VSSAdmin and the command to find out how much space it has its shadowy fingers on is:
VSSAdmin List ShadowStorage
By default, Vista gives 15% of total disk space or 30% of free disk space to System Restore and Volume Shadow Services, whichever is smaller. There’s no slider to adjust as there was in XP and the space doesn’t change unless you turn System Restore on and off - which deletes all the previous versions and restore points, so while it’s easy it’s not really a good idea. But you’re going to want to check and probably change the setting because a lot of PCs seem to think 15% isn’t enough and set the upper limit to - well, all the free disk space you have. In my case Vista had used 15GB of space for previous versions, it had allocated itself 16GB of space and the maximum space was UNBOUNDED. Yes, all my free disk space. I could have gone back to the day I turned on the notebook and got the files I was editing - but that’s not much use if I can’t create any new files.
Put some limits on VSS by typing:
VSSAdmin Resize ShadowStorage /For=C: /On=C: /MaxSize=15GB
I was feeling parsimonious, and I keep most of the files on the SBS 2003 server which also runs VSS, so I gave it 5GB to play with. It allocated just over 2GB and filled 700MB immediately, so I suspect I get the changes on my files yesterday and nothing more. But I also get 39GB of free disk space, so I’m not complaining.
I’m not sure if my notebook came from HP with VSS set to UNBOUNDED in first place or if SP1 might have changed this, so I don’t know who to name and shame. I have seen a lot of Vista users reporting that they’ve been losing disk space the same way, with UNBOUNDED set on machines from Dell, Lenovo and other big-name PC companies. But Microsoft gets a share of the blame, for adding a great feature with no way to control it except from the command line. Worried users will make the VSS space too small? Don’t take the slider away all together; just don’t let it go down below, say, 5GB. I can stop certain file types from getting shadowed by adding them to the HKLM\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToSnapshot registry key. Temporary files are there by default; I’ll probably add MP3 files as I tend not to be editing these… but I’d rather do it without delving into the registry.
And if you’re running Vista Basic or Home Premium, VSS is running for System Restore and backing up your documents, but you can’t right-click to see and retrieve previous versions of a file even though they’re taking up space. Get a copy of ShadowExplorer (only at version 0.2 but also free) from www.shadowexplorer.com and you can make the most of the disk space you agree to give up.
-Mary
Rated: 40% (1 votes)
Loading ...Comment by justine - June 20, 2008 on 6:49 am
i have Windows Vista Home Basic on my home PC and from a 250GB hard drive - brand new PC before i started using it - i only had something like 232GB available. Its bugged me and if you find an easy solution. My home PC is a Gigabyte put together locally but using Intel, Seagate etc. good components. all the best,
Justine
Comment by Simon Bisson & Mary Branscombe - June 20, 2008 on 1:00 pm
Justine; I believe the VSSAdmin commands will work on Home Basic, it’s just the Previous Versions interface you don’t get. Open the command window by right-clicking as described above and type VSSAdmin /? to find out if it’s available; if it is, just follow the instructions to set the volume shadow space to the amount you want to use for it.
Make a comment
Tag cloud
Archives
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- September 2007
- August 2007
- July 2007
- June 2007
- May 2007
- April 2007
- March 2007
- February 2007
- January 2007
- December 2006
- November 2006
- October 2006
- September 2006
Most commented posts
- Java’s SSVAGENT.EXE: training the monkey
5 comments
- Wubi Tuesday
- Not very open, not very social
- The best mobile game ever
- A Big Day In The Enterprise IT World
- Employees are our most valuable asset (snigger)
- Biometrics - it's not the technology that's broken
- More battery life, fewer explosions
- Spam Fighting in Exchange
- IDF: Will SSD mean the end of 5GB free?
Highest Rated Blog Posts
- Nobody knows what Web 2.0 really is (100%)
- Songs of distant satellites (100%)
- Log in and lock in (100%)
- Mommy, why is there a home server in the office? (100%)
- Employees are our most valuable asset (snigger) (100%)
- Locking down IT or blocking creativity (100%)
- Video opera? What would you do with huge bandwidth and millions of pixels? (100%)
- Consumer BlackBerrys are good for business (100%)
- HD Trek (100%)
- Top tips for speeding up Vista (100%)