When you use the Configuration wizard, you have to specify the placement of several components of Exchange and SnapManager like databases, transaction logs, SnapInfo directories, SMTP, and MTA queues.
This Storage Group system path is used only for Exchange system files preceding Exchange 2010. SnapManager places system files for a Storage Group on the same LUN that stores the transaction logs for that Storage Group. The system files for a Storage Group must remain where the Configuration wizard places them.
The transaction logs contain changes made to the Exchange databases since the last backup, enabling an up-to-the-minute restore operation.