The Ethernet section of the FreeBSD Hardware Notes indicates which interfaces are supported by each driver. While many interfaces are supported, FreeNAS® users have seen the best performance from Intel and Chelsio interfaces, so consider these brands when purchasing a new NIC. Realtek cards often perform poorly under CPU load as interfaces with these chipsets do not provide their own processors.
At a minimum, a GigE interface is recommended. While GigE interfaces and switches are affordable for home use, modern disks can easily saturate their 110 MB/s throughput. For higher network throughput, multiple GigE cards can be bonded together using the LACP type of Link Aggregations. The Ethernet switch must support LACP, which means a more expensive managed switch is required.
When network performance is a requirement and there is some money to spend, use 10 GigE interfaces and a managed switch. Managed switches with support for LACP and jumbo frames are preferred, as both can be used to increase network throughput. Refer to the 10 Gig Networking Primer for more information.
At present, these are not supported: InfiniBand, FibreChannel over Ethernet, or wireless interfaces.
Both hardware and the type of shares can affect network performance. On the same hardware, SMB is slower than FTP or NFS because Samba is single-threaded. So a fast CPU can help with SMB performance.
Wake on LAN (WOL) support depends on the FreeBSD driver for the interface. If the driver supports WOL, it can be enabled using ifconfig(8). To determine if WOL is supported on a particular interface, use the interface name with the following command. In this example, the capabilities line indicates that WOL is supported for the re0 interface:
ifconfig -m re0
re0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
capabilities=5399b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_UCAST,WOL_MCAST, WOL_MAGIC,VLAN_HWFILTER,VLAN_H WTSO>
If WOL support is shown but not working for a particular interface, create a bug report using the instructions in Support.