I’m not wild about maintaining extra copies of stuff I’ve also got stored elsewhere (as is the case with all three of the aforementioned items, one of which backs up a system with mirrored drives), and I’m not wild about giving up 30% of my drive’s storage space for a form of data and files insurance. From the directory listing above, in fact, it’s pretty clear that backups (the 21 GB file), big file transfers (the 84 GB wholesale transfer of digital music to this drive), and a disk image of the parent system (the 67 GB file dated 2/7/08) caused VSS to blow its storage limits right past the ceiling.
#Windows shadow copy space requirements windows
What I infer from the data shown here is that Windows Vista generally stays within the 15% limit for shadow copies, but that big backups or file copies can exceed those bounds. I did a little reconnoitering and observed the following shadow space consumption for all SATA drives on my system (shadow copies only occur on direct attached drives, not on USB-attached ones, which helps me understand why USB drives are recommended for backup storage): Table of Shadow storage info from my systemĬ: 298 (320) GB 89.3 GB 41.845 GB 46.0 14.04%ĭ: 698 (750) GB 349.0 GB 202.399 GB 58.0 28.99%į: 149 (160) GB 23.0 GB 10.144 GB 44.1 6.81% What’s upsetting as well as interesting here is that although MS indicates about 15% of a volume’s storage space is typically allocated for shadow copies, this collection is over 200 GB, and consumes nearly 29% of the total drive space! My observation is that when you backup, create a shared volume, or do any kind of massive file transfer onto a drive, VSS creates a shadow copy at about the same time NTFS creates the original copy. 07:14 PM 21,939,716,096 Ĭheck out the size for some of these files! When I looked at them, I noticed that the 80-odd GB file dated corresponded to my copy of my complete digital music collection to that drive, while the 60-odd GB item on 2/7/08 corresponds to my first image backup of the system to which this drive was attached. They’re also invariably fairly recent in date, because the Restore Point system tracks its space consumption carefully and deletes older restore points as it creates new ones to keep such consumption under control.ĭ:\ > dir “System Volume Information” /allĭirectory of d:\System Volume Information These are generally much smaller (2 to 7 GB) and are gathered more often than backups, shared folder snapshots, or big file transfers. (I’ll remark further on some of these files after said listing these cryptic filenames have been abbreviated-their names aren’t human-readable anyway so it doesn’t matter anyway.) But it’s also worth remember that another kind of file resides in this directory-namely, restore points. Here’s a listing that seems totally mysterious, until you understand that most of these files, especially the biggest ones, are shadow copies of some kind.
Modern Windows versions make shadow copies more frequently than tape backups, and VSS stores shadow copies inside opaque file containers in the System Volume Information directory on any given NTFS drive.
#Windows shadow copy space requirements software
Fourth and last, shadow copies support fast recovery of damaged files or volumes for Active Directory, Exchange, and other server applications to help users cope with hardware failures, storage problems, or software corruption issues. Third, they enable creation of transportable shadows for speedy network delivery so that a server backup image can more efficiently traverse the network from its source to a server with a tape backup unit for archiving and storage. Second, they provide access to multiple copies of shared folders so that users can recover deleted files without administrator assistance, and enable desktop users to access prior versions of files when shadow copies exist. First, they capture consistent backups of open files and applications in use, so that work can proceed even while a backup is underway. Shadow copies offer special capabilities for modern Windows file systems. Microsoft likes to call this service its backup infrastructure for Windows XP and Vista on the desktop, and versions 20 on the server side. Microsoft abbreviates this service as VSS, for some odd reason or another omitting the C, as in the command line program that manages its behavior: vssadmin.
The Windows Volume Shadow Copy Service exists to produce clean snapshots of disk volumes, and to create shadow copies of data or files that are consistent, readable, and associated with some specific timestamp.