Volume shadow copy backup services or VSS are one of the commonly used back up services that can be used in both the active and passive databases and storage groups. VSS cannot support the streaming backups alone; in that case VSS need to be aligned along with VSS requestor for proper functioning.
Streaming backups are something advanced that could handle two storage groups at same time whereas volume shadow copy backup service can handle only one storage group at a time. But the advantage is that two VSS jobs can be run in same exchange server at same time.
One of the disadvantages of the service is that the restore operations can be copied only to the original path, not to the location you prefer. But the data selected for restore can be copied to any storage group of your choice.
The VSS writer also enables restoring of data to any other folder that has no connection with the storage database group you are using. In this case, you have to use any kind of jet database engine to restart the files and convert them into fully functional form. Once they are activated, the folder, files or even the entire database can be moved to the location you wish.
Solving issues related to volume shadow copy backup service is another thing that needs much care. In order to troubleshoot the VSS problems, it is better to install the full service package also while installing the updates for the service. These rollup packs can solve most of the errors in the servicing system.
Preventing errors from occurring is better than detecting them and solving after they have affected the service. Checking the status of exchange writer and confirming it to the stable state before initializing the backup operations can prevent most of the future errors.