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No Read-Only File-System in WPSD

Most users are accustomed to the “other sftware” having a forced Read-Only file system by default. While this can be useful, it’s unnecessary in WPSD and in fact, is a pain in the ass sometimes.

WPSD’s filesystem is not read-only…

Rationale for enabling a persistent Read-Write file-system

The dashboard and underlying software only writes significant data to log files, which are used/parsed by the dashboard software to display meaningful data. However, these log files aren’t even written to/read from disk; they are actually stored to memory using tempfs.

Other than that, there is very little else for write activity, and most of it is also written to memory, vs. disk (see ASCII figure below).

And when a user needs to make configuration changes, setups, etc., the file system in Read-Only mode often creates issues where settings may not be saved properly. A huge pain in the ass!

Frankly, I feel a Read-Only file system in WPSD is a false sense of security, does not do much in prolonging SD card life1 since most data is in memory, and it honestly introduces needless complexity.

ASCII table of most tempfs-enabled (memory) mountpoints in WPSD

tmpfs                   /run
tmpfs                   /run/lock
tmpfs                   /sys/fs/cgroup
tmpfs                   /tmp
tmpfs                   /var/log
tmpfs                   /var/lib/sudo
tmpfs                   /var/lib/dhcpcd
tmpfs                   /var/lib/logrotate
tmpfs                   /var/lib/nginx/body
tmpfs                   /var/lib/php/sessions
tmpfs                   /var/lib/samba/private
tmpfs                   /var/lib/vnstat

  1. Here’s an example of SD card longevity provided by my colleague, Tom. He’s been running read/write-heavy software on this instance for over 8 years without issue. Get a decent SD card and you’ll be just fine: http://www.threefools.org/weewx/status/index.html. I also run the same software as Tom, and my instance has been running non-stop on the same good-quality SD card since 2015. 

Document Version: 5a4b1b3 -- Last Revision: 2025-11-29
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