[Mono-list] Stability fo mod_mono

Joshua Tauberer jit at occams.info
Sun Apr 27 07:10:41 EDT 2008

Julien Sobrier wrote:
> we're running mod_mono on a server for a few weeks and we have a lot of
> stability issues:
> 1/ every time we upload new code, we have to restart mod_mono, otherwise
> it doesn't work most of the time (the process is up but acccces to a
> pcage times out). Is it normal?

I'm not sure if it's not a bug, but I do the same thing (using the 
mod_mono control panel), so to some extent it's normal.

> 2/ Once we restart mod_mono, if we access an aspx page to quickly,
> mod_mono times out: the process is up, but the page is not displayed. I
> usually wait at least 30s

That's not right. First accesses to pages can take a while as things are 
loaded up, but it should be <10s, unless something unusual is happening 
in your code.

> 3/ Quite often, mod_mono seems to be down. The process is still up, but
> no pagedisplayed. using the mod_mono control panel to restart  mod_mono
> doesn't work (503 errors), we have to stop Apache, kill mod_mono,
> restart Apache
> The server gets less than 1,000 hits a day coming from about 3 unique
> users.

I experience intermittent things as well, but on the order of just a few 
times under 50,000 hits, a day. Still, I continue to do a 
stop/killall/start every six hours.

I also found that in some cases the control panel restart would send 
mod_mono into a big mess of forking new backend processes indefinitely. 
I think I've fixed this but I haven't yet committed the changes.

> The mono version:
> mono: 1.2.6

You could try a later version though I'm not sure the changes since then 
are relevant.

> Any idea how I can find out more infromation about mod_mono being down?

You can compile mod_mono from source with the debugging flag. It'll 
output a lot to the error_log, but it would be useful.

> [Fri Apr 25 22:20:51 2008] [error] Not running mod-mono-server.exe
> because no Mo
> noApplications, MonoApplicationsConfigFile or MonoApplicationConfigDir
> specified

I'm not sure where this is coming from but if it works at all, that 
seems to be spurious.

> [Fri Apr 25 22:20:37 2008] [warn] (22)Invalid argument: Failed to
> destroy the '/
> tmp/mod_mono_dashboard_XXGLOBAL_1' shared memory dashboard
> [...]
> [Sat Apr 26 09:58:14 2008] [warn] (22)Invalid argument: Failed to
> destroy the '/
> tmp/mod_mono_dashboard_default_3' shared memory dashboard

I fixed this after 1.2.6, but I don't think it's related to your problems.

So one problem at a time- On the first access after a restart, is the 
timeout occurring in ASP.NET? (i.e. it times itself out)

- Josh Tauberer


"Yields falsehood when preceded by its quotation!  Yields
falsehood when preceded by its quotation!" Achilles to
Tortoise (in "Godel, Escher, Bach" by Douglas Hofstadter)

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