The Raspberry Pi Zero W is a capable FTP/SSH server, but for field deployments, I would consider Compute Module 3 or Raspberry Pi 4.
This article is mainly about can be easily done with a Raspberry Pi Zero W vs. Compute Module 3.
- Cannot Install / Not working if Installed
- Extremely slow, maybe single patient user only
- slow, but perhaps usable for patient 1-3 users
- adequate, may handle a handful of users (family, small club)
- great, handles multiple concurrent users, not so much slower than a 10-year old Pentium 4 PC
Groupware (email/calendar) server
Citadel is an easy to install groupware server. Accessing features took a few seconds per click, and it didn’t seem that users would have the patience for Citadel on Raspberry Pi Zero.
Like SSH below, the Raspberry Pi Zero can handle a few connections at once, but is limited to less than raw Ethernet speeds due to:
- CPU: USB-Ethernet onboard conversion
- CPU: encryption (if using SSL/SSH, etc.)
- CPU: filesystem – if using external HDD with FUSE (NTFS,exfat,etc.)
- CPU: USB HDD – takes some CPU to manage the transfer from USB to external HDD
- SD card: read/write speed
Web LAMP server
The Raspberry Pi as an NGINX or other lightweight server can work fine–test if your application might need the Compute Module 3 vs. Pi Zero.
Rank: 2 - 2.5
With Raspbian, the Raspberry Pi Zero is too slow to be used as a desktop replacement. The Raspberry Pi 4 and Compute Module 3 are fast enough for light desktop use.
SSH server (port forwarding, SSHFS, remote management)
Rank: 4 - 4.5
The Raspberry Pi Zero W does quite adequately in this regard – you will feel just a bit of the CPU limitation when using many sessions or high Ethernet bandwidth.
The Raspberry Pi FM transmitter works splendidly – the program can be modified to transmit narrowband (~ 5kHz) FM on the 2 meter ham band, and for a wide variety of software defined radio tasks.