Perlbal with Mongrels

Adam Jacob adam at
Thu Nov 1 23:38:33 UTC 2007

I sent a patch to allow this to be a bit more tuneable, which allows
this to work with Rails.  (If anyone can figure out how to get Rails
to respond to an OPTION * request, you are my hero.)  It apparently
got lost in the shuffle for the last release, so here it is, updated
for the current trunk (should apply directly to 1.60 as well)

It allows you to set a verify_backend_path, which defaults to the
current '*'.  For rails, you can set it to /, or any other url you
would like to route your OPTIONs request to.

Perlbal + Mongrel with verify_backend solves a pretty irritating
behavior on mongrel's part, which is the caching of connections while
it waits on the Rails process to complete.  I'm using this
patched-perlbal in production on several different Rails apps, and it
works great.


On 10/31/07, TJ Murphy <TJ at> wrote:
> Allo,
> I'm currently running Perlbal (1.59, reverse_proxy) to load balance a bunch
> of mongrels.  Occasionally I get to a point where Perlbal will serve return
> a blank white screen instead of returning the app response.  My users have
> dubbed it the "White Screen Of Death".  I'm not sure where to begin
> debugging the problem or sorting out the cause.
> I see the issue happen when I have a spike in requests or if I kill off the
> mongrels.  I have found that adding more mongrels usually leads to less
> white screens.
> Also, it seems that verify_backend doesn't really jive with mongrel.  I
> suspect it's because mongrel doesn't respond to an OPTIONS request.  Is
> there any way to benefit from verify_backend in my case?

HJK Solutions - We Launch Startups -
Adam Jacob, Senior Partner
T: (206) 508-4759 E: adam at
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