Justin, thanks for looking into this challenge.  Please keep us informed.  

Here's a script you can run on Linux to see how much disk space you have (actual disk space).  May not work on all servers.  Just ran it on a server that was having problems and one drive was at 100% and the other was 96%.  It's a wonder anything still works at that point.  

We're at 84% here at E-Blah. Anything over 80% is yellow in my opinion.

Code #!/usr/bin/perl print "Content-type: text/html\n\n"; print "<pre>"; print `df`; exit; 1;

Chmod 755.  Note that you need to use the drive your site's on, /tmp for example may be at 0%, but your site isn't located there .  

Quoted from Justin

  The most probable (and usually reasons) why this fails is because server space is low, the E-Blah process is killed (during a write operation), or file locking is not supported by the file system.

Firstly, my own problems weren't due to Eblah, but to Heart's documentation within their free offering, which was just wrong, and seems to me designed to persuade me to move to a package that includes more support.

Secondly, I've been watching this subject for a while. If it can be pinned down to a perl failure in writing one .dat file, can't the proposed new written-to .dat file be compared in size with the old .dat file, and if there is an unexpectedly large discrepancy, the process aborted and then repeated afresh?

I know next to nothing about perl, programming, etc., but I was curious as to what's possible, really....

Yes, you could (create a .bak file), but that also creates more overhead and I'm not sure a move/rename operation wouldn't blank the file out either.  It would be relatively easy to implement, but I'm not really sure it would solve the problem either.  I've seen other Perl software go this route to try to fix it, but I don't believe it solved the problem either.

The good news is that E-Blah itself isn't the cause of the problems -- it's servers that run low on disk space and aren't properly handled.  The bad news is it's always going to happen that people forget to keep watch of their disk space.  

Quoted from Justin

Yes, you could (create a .bak file), but that also creates more overhead

I was thinking more of a "forward" file than a "Bak" file, but I get what you're saying:  if the disk space isn't there any operation  is going to produce erratic results, if any, and that's what the problem is and where the solution must lie.

Leave lots of leeway.