Backup does not contain ost files


#1

Dear reader,
I’m backup up my users profile while running duplicati as a service with snapshot set to “on”.
I have selected the complete users profile. It backups up successfull. Now i want to check if the OST file were backed up while outlook was opened by chose a restore. But the files are not available in:
C:\Users\username\AppData\Local\Microsoft\Outlook

I tried backing up with outlook closed. But they still are not there? Any idea what could go wrong?
best regards,
Ruud.


#2

Gonna make a sport out of answering my own questions…stumbled across the following:

A Microsoft employee contacted us after he discovered that his 4-GB Microsoft Outlook .ost file was not present after he restored an image made by Complete PC Backup. Given the feature name “Complete PC Backup,” he expected that all files would be restored and was concerned about having to regenerate his giant .ost file. No doubt other Windows Vista users will encounter this behavior, so we wanted to explain why .ost files are not part of Complete PC Backup images.
Maintaining changes to .ost files within shadow copies is expensive in terms of space and I/O activity. The performance impact doesn’t occur during the image backup itself–the only extra work at backup time is backing up the .ost file as part of the image. Instead, the performance impact occurs during the ongoing, everyday I/O to the .ost file when Outlook is running. If the .ost changes were kept in shadow copies, then every time Outlook writes to the .ost file, the result is a copy-on-write I/O hit (2 writes, 1 read). Although we have worked to reduce the impact of copy-on-writes on shadow copies, a heavily churned file like an .ost file could still cause problems. For these reasons, and the fact that .ost files can be regenerated, we chose to delete .ost files from the shadow copy before the image is created.
Even if the performance issues didn’t exist, there are situations where Exchange will, after an .ost is restored, detect a “future” version of the .ost file and force you to delete and then regenerate the local .ost file. Therefore, it’s still preferable to regenerate an .ost file instead of restoring it.


#3

Could you provide a link to where you found that, that is really interesting info. I wasn’t aware that VSS would exclude some files from being snapshotted.


#4

Hi Dave,
Check this.
https://msdn.microsoft.com/en-us/library/windows/desktop/aa819132(v=vs.85).aspx
I have checked the registry on my machine, and the files not to snapshot contains the OAB and OST.