Occasionally, a map may be lost, perhaps deleted inadvertently or through corruption of the file. In the latter case, we can sometimes recover at least some of the map. If the file has been truncated, the degree of success is determined by at what point the file has been truncated. If too little is recoverable, then resorting to a back-up copy may be necessary.
An additional possibility is restoring a file using 'Previous Versions', a feature of Windows. Previous Versions can be a standalone feature in client versions of Windows, such as Windows 7, but is arguably much more useful when used in conjunction with Shadow Copies of Shared Folders, a feature of Windows Server.
Shadow Copies of Shared Folders are copies of files in shared folders taken at particular times determined by a configurable schedule.
There can be up to 64 copies, so the age of the oldest copy will be determined by the frequency of copying. The default is twice a day, but this can be changed by reconfiguring the associated scheduled task.
These copies are available to users as previous versions, accessible through a file or folder's 'Properties' dialog.
This feature allows you to:
Shadow Copies apply to all shared folders on a volume for which it's enabled.
The feature is enabled in Windows Server through 'Computer Management' - Shared Folders > All Tasks > Configure Shadow Copies...
When enabled, a scheduled task is created automatically to take copies at 07:00 and 12:00, but this can be reconfigured in Task Scheduler.
Microsoft's recommendations include:
Store shadow copies on a separate volume
Storing shadow copies on a separate volume from the source files should enhance reliability and performance. Adding a separate volume should be simple, particularly on virtual servers, which are common these days.
Consider how files are used before configuring shadow copies and their schedules
If a single server hosts all three roles (file, web and publication servers), all files are within the 'Triaster' folder and that folder is shared, then all Triaster files will be subject to shadow copying. However, that's not always the case. The map store may be on a different volume or on a separate file server. In that scenario, the maps may be configured separately for shadow copying.
Questions that should be considered include:
Perform regular back-ups of your files
Shadow copying should be in addition to taking file back-ups, not a replacement technique.
Do not schedule copies more frequently than once an hour
Server performance could be hampered if shadow copies were taken too frequently. The limit of 64 copies per volume determines how old the oldest copy can be.
With shadow copies of folders and files available, retrieving older copies is straightforward.
Recovering a deleted file
Recovering a previous version of a file
Check an older version of a file
Windows Previous Versions in conjunction with Shadow Copies of Shared Folders provides convenient methods for retrieving lost and older versions of folders and files without further intervention needed from technical staff. Just ensure sufficient thought is given to the implementation!