macOS Sierra: About Xsan storage volumes
If your computer is connected to an Xsan storage area network (SAN), a SAN volume might be available (mounted) on your computer. You can connect your computer to a SAN by installing a configuration profile provided by your Xsan administrator or by having the Xsan administrator enroll the computer in Profile Manager, which is included with the Server app.
You can use an Xsan volume just like any other storage device, subject to the permissions and quotas established by the Xsan administrator. If you try to store more on an Xsan volume than your quota allows, you see a message saying you’ve exceeded your allocated space. To find out the size of your quota, check with the administrator.
Xsan volumes are based on Redundant Array of Independent Disks (RAID) storage devices. The Xsan administrator sets up and manages Xsan volumes using the Server app, and can use it to create a configuration profile to join your computer to the SAN. Your Xsan administrator can also join your computer to the SAN by using Profile Manager. Once your computer is joined to a SAN, Xsan volumes remain mounted on your computer until you or the administrator removes the Xsan configuration profile (even if you log out of macOS or restart your Mac).
To get help with Xsan administration, see the Xsan Guide. You can download it from the iBooks Store on your Mac or iOS device.