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 accustomed to using Google or Office 365 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.