A specific file has been corrupted on many home directories. Within a Volume Shadow Copy backup is a good copy of the file.
The corruption is easy to detect, but how do you code something to automatically go through previous versions on multiple servers.
Here are my findings with some snippets of C# to help.
When you open a previous version, explorer shows the date in brackets: \\server\folder (01 February 2013, 12:34)
But try that same path in the command line or code and it will fail. Shift Right Click on a folder, 'Open command window here' and you get: Z:\@GMT-2013.02.01-12.34.56\folder\
Using a VSS time in a file path:
That @GMT path can go anywhere you would expect a directory, for example: \\server\@GMT-2013.02.01-12.34.56\folder\file.txt \\server\folder\@GMT-2013.02.01-12.34.56\file.txt Both shares go to the same place, providing a copy the previous version.
Finding a valid VSS date and time:
The GMT/UTC path has to be the exact moment the 'Shadow Copy' was started.
Tests showed the starting seconds varied daily, even the starting hour changed as the VSS schedule was local time and 'daylight savings' had taken effect. In short, using the schedule and guessing paths was not going to be practical.
As a starting point I found the command line: VSSAdmin List Shadows But this has no remote parameter, gave local time, and would require parsing.
Remote WMI query to rescue:
Using "SELECT * FROM Win32_ShadowCopy" and the "InstallDate" property you can get a list of shadow start times, but they need converting from local time:
var dmtf = wmiProperty["InstallDate"].ToString(); var vssTime = ManagementDateTimeConverter.ToDateTime(dmtf).ToUniversalTime();
WMI results can be returned in any order and we want the newest shadow first, so we put the query results into a list and date sort descending:
vssTimeList.Sort((a, b) => b.CompareTo(a));
The dates can then be converted into a usable directory path format:
var vssPath = "@GMT-" + vssTime.ToString("yyyy.MM.dd-H.mm.ss");
Using the VSS paths:
The shadow times returned are for ALL drives on the server, so when looping through the times and combining them into a share path, some may be invalid when the time is for a shadow on another drive.
It silently installs an invisible license manager that screws with your PC.
I needed to do some lite video editing and a site recommended Lightworks. Used by the professionals and a free version? Great! I will give it ago. Except it fails to mention it requires an account, so immediately uninstalled.
But later noticed something weird, my hard drives were no longer winding down. ( I have a very quiet PC with a SSD, so you hear when drives are spinning )
Fired up ProcessMonitor and see a 'hasplms.exe' constantly polling everything. Not something I had seen before and no new entries on Programs list.
Quick google search gave me a helpful blog, had to download the license installer and run it with the purge command. Shortly after my disks spun down. Hurray. And that's the story of how I wished harm upon developers I have never met.
Came across an undeletable file today at work on a network drive.
The only thing that stood out was it had an @ ( AT symbol ) in the name. It wasn't hidden or system, just plain ascii, but gave either: "Could not find this item" or "You need permission to perform this action". The normal tricks of using Attrib, 8DOT3 name, Robocopy, all failed.
Narrowed it down to any file, in a subfolder, over a network share, with: @GMT-0000.00.00-00.00.00 ( zeroes can be any digit ) anywhere in the file name becomes protected from rename or deletion.
Seems it was intended to guard Volume Shadow Copy data files, but anyone is allowed to create or rename a file with the above in the name.
The solution was to log on to the server and delete directly from the local drive.