Re: What does this error really mean?

[Jan-Henrik Haukeland]

On 18. okt. 2005, at 18.59, Ben Hartshorne wrote:

> The previous section generated:
>
> HTTP: error receiving data -- Resource temporarily unavailable
>
> Does that error mean basically the same thing (that the connection
> endpoint did not send data that monit was expecting to recieve), but
> over HTTP instead of send/expect?

Yes. Typically this will happen if the server shutdown a connection  
or refuse to send any data. A very busy (HTTP) server can do that.


> How is this different from the "service timed out" error?

This is not necessarily a connection error, but from the service  
timeout statement (see http://www.tildeslash.com/monit/doc/ 
manual.php#service_timeout). It basically means (as you probably  
know) that monit had to restart a service to many time within a period.

> Does one imply that it was never able to connect, and the other  
> that a connection
> was made but not completed?

The "error receiving data" error imply, as you assume, that a  
connection was successfully made, but that data transfer failed for  
some reason. If a connection should fail, you will see this explicit  
in the log as "failed, cannot open a connection to..".

> Both of these scenarios are different from
> getting the wrong data, right?

The error messages discussed here are from the TCP stack and has  
nothing to do with the overlying protocol tested.

> I'm getting these Resource temporarily unavailable errors in the  
> middle
> of the night (my tests go over a local ethernet network). I'm  
> really not
> sure why they're occuring.

Cant help you there. Maybe a DHCP lease going south or whatnot. It  
should also be noted that the way monit currently read a line from a  
socket is by reading one-by-one byte, which may be vulnerable if the  
network is a bit shaky. I have updated the latest CVS to fix this. It  
may or may not help. I would be interested to know _if_ it helped  
though.

--
Jan-Henrik Haukeland
Mobil +47 97141255