[smokeping-users] mod_fcgid: HTTP request length xxx (so far) exceeds MaxRequestLen (yyyy)

Paul Mansfield paul.mansfield+smokeping at grapeshot.co.uk
Mon Jan 27 14:42:10 CET 2014

We have had a significant number of problems with smokeping client
consuming all the memory on a server, we've had these grow to 12GB in
the worst case!

There appear to be two problems, probably related.

* One is that the slave can't communicate with the master for a while
and the smokeping slave cache builds up a backlog of work, and then it
is unable to send the data.

* The other problem is that the slave process, e.g. usually FPing,
gets wedged and becomes larger and larger.

the clue to the first problem are lines like this in the Apache error log:

[Mon Jan 27 12:12:42 2014] [warn] [client w.x.y.z] mod_fcgid: HTTP
request length 394304 (so far) exceeds MaxRequestLen (393216)

To resolve this, you have to kill-9 the smokeping slave, and any child
processes like FPing, then remove everything in the ~smokeping/cache
directory. Then it's safe to restart.

It's probably worth setting a larger number than the default in apache
config anyway to allow slaves to catch up... e.g.
    FcgidMaxRequestLen 131072

but if you find anything larger than that it probably means something
else has gone wrong.

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