How to debug a server reset or WSOD? We have recently observed that we can put Drupal in an inconsistent state where it responds with a server reset or WSOD, where no data is sent. This by simply having some faulty configuration (See CCK field migration reproducibly results in server error )

We have started to doubt the robustness of the our Drupal instance (and even Drupal in general if it is so easy to push off the tracks), so we want to look into this event further and understand exactly why, because in any case even a cryptic error message would be preferred over just dying.

How to debug such a situation, properly? There is no output whatsoever, neither in the logs nor to the browser. We have enabled the devel module debug outptu an krumo output, but it dies before this. We have also tried to catch sql queries using pg_top, nothing. 

What do?
To debug more on WSOD, you can always go to Server (Apache2/httpd) error logs or if accessible Recent logs Messages (Admin => Reports => Recent Log Messages) in Drupal.

You can find more details about WSOD and debugging it on below link:
Blank pages or "white screen of death" (WSOD)

Hope this helps.