====== Raspberry Pi NAS: Networking ======

Current release of **RaspiOS** (we are on Debian 10 Buster) uses **dhcpcd** to manage networking (see **[[https://www.raspberrypi.org/documentation/configuration/tcpip/|Raspberry Pi TCP/IP Networking]]**). This means that:

  * Use **/etc/dhcpcd.conf** file to define static IP address or fallback IP address (if DHCP fails). The same file is used to e.g. disable **WiFi** (wlan0) interface.
  * Do not use **/etc/network/interfaces** for static or dynamic IP assignment.
  * WiFi ESSIDs and passwords are in **/etc/wpa_supplicant/wpa_supplicant.conf**.
  * Do not install **Network Manager**.
  * If a gaphical interface is needed, use **lxplug-network**.
  * If some package installs the systemd **wpa_supplicant.service**, disable it or you will have two conflicting ''wpa_supplicant'' processes running (execute the ''systemctl disable wpa_supplicant.service'' command and reboot).

I want the **eth0** interface to have a static IP address beside the one eventually assigned by DHCP (i.e. I want an IP alias on eth0:0). This is useful when I wan connect to the host even in an unknown network. To achieve this when dhcpcd is running, it is necessary to create an **user defined hook script**. See this page for more details: **[[..:linux:sa:dhcpcd_ip_alias]]**.

===== Samba =====

FIXME

===== Transfer rate =====

We measured the **transfer rate** from other home NASes, just to figure out how much time is required to **transfer 500 Gb of data**. The receiving NAS is the **Raspberry Pi 4** with a **Seagate 4 Tb** IronWolf 3.5 inch hard disk connected through the **X835 USB3** interface. The network is limited to **100 Mbit** transfer rate, due to the limit of the LAN switch.

^ NAS model          ^ Disk model  ^ Transfer rate (Mbit)  ^ 500 Gb transfer time (hours)  ^
| LaCie d2 Network   | WDC WD10EFRX-68FYTN0, 1Tb, 5400 rpm       |   13 |  87.5 |
| QNAP TS-120        | Hitachi Deskstar 7K1000.B, 1Tb, 7200 rpm  |   98 |  12.7 |

===== Hard disk performance =====

To measure the hard disk **read performance** we copied a large file of about **3 Gb** into **/dev/null**, this is the result timing:

^ Interface  ^   Mb/s ^
| USB 2      |   31.8 |
| USB 3.0    |  184.8 |

If you are interested in transferring large files across the network, beware that a **100 Mbit LAN** imposes a limit of **14.7 Mb per second**, so the **USB 2** interface is enough to sustain that. But if you are interested into **Gigabit Ethernet** performance offered by the **Raspberry Pi 4**, you definitely need to use the **USB 3.0** interface.