Files Randomly Truncated

[samrueby]

I have been seeing a difficult-to-track-down problem where files seemingly randomly get truncated. I have a strong belief this happens during horizontal scaling. I most-recently saw this with the file /home/site/wwwroot/wp-content/advanced-cache.php, which is used by WP Super Cache, where the file was truncated. This took down our site until I removed the file so the plugin could recreate it.

Is there a quirk with NFS that we should be careful-of? Do plugins need to explicitly handle shared file systems?

[victorlin]

For the advanced-cache.php file specifically, I've received an email notification about it when removing the plugin. Not sure if it's related.

Dear User,

WP Super Cache was removed from your blog or deactivated but some files could
not be deleted.

/var/www/wordpress/wp-content/advanced-cache.php

You should delete these files manually.
You may need to change the permissions of the files or parent directory.
You can read more about this in the Codex at
https://codex.wordpress.org/Changing_File_Permissions#About_Chmod

Thank you.