Fibre Channel fabric
Unlike file system metadata, which controllers and clients exchange over Ethernet, file content in an Xsan SAN is transferred over Fibre Channel connections (as is metadata that controllers access on a volume). The computers, storage devices, and switches are connected with Fibre Channel cables to form a Fibre Channel fabric. To set up the connections, you need:
An Apple Fibre Channel card or other Fibre Channel adapter for each client and controller computer
A supported Fibre Channel switch
Fibre Channel cables connecting computers and storage devices to the switches to form a Fibre Channel fabric
Fibre Channel cards or adapters: Install an Apple Fibre Channel PCI card or attach a Fibre Channel adapter to a compatible port of each Mac that connects to the SAN.
Fibre Channel switches: Fibre Channel switches from Brocade, Cisco, and QLogic have been tested with Xsan and the Apple Fibre Channel PCI, PCI-X, and PCI-E cards.
Fabric configuration: You must connect the computers, storage devices, and switches in your Fibre Channel network to form a Fibre Channel fabric. In a fabric, Fibre Channel cables connect node ports (F or N_Port). For more information about setting up your fabric, see the documentation that came with your Fibre Channel switches.
Ethernet TCP/IP network
Computers on the SAN must be connected to an Ethernet network. Xsan controllers and clients use this network instead of the Fibre Channel network to exchange file system metadata.
IP addresses: The client and metadata controller computers need static (fixed) IP addresses for Ethernet network connections. For the public intranet and Internet connection, you can enter each computer’s static IP address, subnet mask, router address, and DNS server address manually or configure a DHCP server to provide this information.
Using DHCP: If you want the DHCP server to provide IP addresses, it must always assign the same static IP address to each SAN computer. Don’t use DHCP to assign dynamic IP addresses to SAN devices.
Private addressing: For the SAN metadata network, the SAN computers should have static private (nonroutable) IP addresses (unless you can’t set up a separate, private Ethernet network for SAN metadata).
Directory services
To use Apple Xsan, you must have an Open Directory infrastructure. The primary metadata controller must be an Open Directory master, and all additional controllers must be Open Directory replicas. Before creating your SAN, Open Directory must be configured and enabled.
The directory is also used to manage user and group privileges to control access to files and folders on the SAN. A central directory service lets you manage SAN users and groups from one computer instead of having to visit and painstakingly configure each SAN client and metadata controller.
If you have another type of directory service, such as Active Directory, you configure each Mac in the SAN to connect to it for user and group accounts by using the Users & Groups pane of System Preferences after initial setup.
If your SAN doesn’t have access to an existing directory service, the server setup assistant creates an Open Directory master server on your primary metadata controller.
The Open Directory master provides an LDAP directory, single sign-on user authentication using Kerberos, and password validation using common authentication methods. The replicas improve responsiveness and provide automatic failover of Open Directory services.
Note: Some apps running on SAN client computers, such as Final Cut Pro, work better when users have local home folders, not network home folders. User accounts that you manage with Server are set up with local home folders.