Please shutdown the unit first and pull the U300 controller out of the chassis, then follow the U300series upgrade white paper that is downloadable from the Qsan Partner Portal to upgrade the U300-P10 unit to have 10G/FC frontend interfaces.
Yes, user can delete one snapshot alone, it won't be caused any issues. There is no dependencies for delete actions.
No, all NAS series don't support iSCSI LUN masking feature due to patent. 
Yes, user can backup/restore the user account in WebUI. Please go to the configuration page, selecting the Account in the left part, then the user can export/import account via this page.
The system information is only used by Qsan support team to help troubleshooting your Qsan storage device when necessary. For security reasons this file is encrypted for Qsan engineers to decrypt and analyze only.
For the system stability, we only allow users to access the system with basic pre-definedCLI commands.
A clone is an writable connection of a volume or a file system, and it only can be created from the snapshot.
But the clone will be deleted together when the snapshot is created from is deleted.
Qcentral is an utility developed by Qsan for management of multiple Qsan storage units within a single user interface. You may download the Qcentral utility from Qsan partner portal.
The clone task will be deleted together when the origin snapshot had been deleted.
The maximum number of shares that user can create is 512.