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In the online help for Ghost 14, the documentation for Command files refers to applications as potentially being "VSS aware". But, I can't find anywhere that tells me what "VSS" is or how to tell if a given application IS VSS aware.
What is VSS?
How do I tell if Outlook 2003 is VSS aware?
Hi Stuart!
I'm going to give you my understanding in layman's terms (i'm not an engineer here at Symantec but a product manager). :)
Microsoft's Virtual Shadow Service is a framework and API for automating backups on volumes where large amounts of data are changing. In the past, you had to stop the I/O on a volume, take the snapshot and then restart the I/O. VSS automates this by talking directly to "writer" services such as Microsoft Exchange/Outlook.
Norton Ghost 14 includes technology that talks directly to the Microsoft VSS service, letting it know that a volume will be affected. VSS communicates with the running Exchange application (the writer) to pause new transactions, finish current transactions, and flush all the cached data to disk. Once a shadow copy is created, VSS then tells Exchange it can begin writing to disk again. Ghost then creates the backup from the shadow copy - reducing the performance impact on Exchange.
So to answer your questions, VSS first makes sure your file will be "transactionally consistent" by finishing current transactions first. Any changes after the VSS service tells the application to restart I/O will not be backed up and you'll get those on your next backup. Regarding where your messages will be if they've been moved to by an Outlook rule prior to the backup...they should be in the same folder after the backup is restored.
Hope this helps.
RR
Thanks, Robert.
I actually understood all that from the MS documentation on VSS once I got past the incorrect information from Symantec Tech Support that VSS is a Symantec product. I write Windows system software for a living - but I had never heard of VSS (except as Visual SourceSafe) before I bought Ghost.
Be aware that Exchange is not running on my PC. In fact, in my particular scenario, Exchange is not running anywhere. My local copy of Outlook 2003 is using POP3 to talk to an Ipswitch mail server. Not that any of that is really relevant to the *real* issue at hand...
And my question about where a message would be was regarding if the rule was running during the backup, not if it happened "prior to the backup". Again, irrelevant. If the application is VSS-aware and properly compliant, the message will be in one of the two folders, and not lost, which is the important thing.
For the possible benefit of future readers, I wanted to add here that my research with Microsoft indicates that VSS is actually an acronym for Volume Shadow Copy Service.
I got Tech Support online in a chat. The guy said that VSS stands for Virtual Shadow Service.
He said that VSS enables Ghost to backup files that are open. E.g. an Outlook.pst file, if Outlook is running.
But, he could not tell me how it works, so I don't have any reason to have any confidence in it.
For example, if it works by making a shadow copy of the file somewhere, when does it do that? How do I know that the copy was made at a time when the file is transactionally consistent? If it makes the copy when the application first loads, will I lose all changes to the file since I started the application?
I normally having Outlook running for days at a time. If I'm going to lose everything that happened since the last time I opened Outlook, the backup won't really be useful to me.
How much data *could* I lose from my Outlook file? If Outlook is downloading message 51 of 100 when the backup is made, then when I recover Outlook.pst, will I have the first 50 messages in my file? Or will it lose them?
If I have a Rule running, which moves a message from my Inbox to some other folder, when the backup runs, where will the message be in the recovered file? Or will it even be there at all? Could it get lost between folders if the destination folder is backed up before the message is put in it and the Inbox is backed up after the message is moved out of it?
The Tech Support guy basically just said, "turn this option on, and it will work." I told him that was kind of like a car salesman telling me that he'd give me free oil changes for 100,000 miles, but he won't put it in writing and he won't let me talk to a manager for confirmation. SURE, you will! I'll buy that car now! Right!