Sudden hit_for_pass

[James Harrison]

Hi,

I have a varnish server sat in front of a website which was previously
sitting at 60% hitrate, no hit_for_pass. With no configuration change
aside from adding a single ban rule (which I have since removed) keyed
to a hostname the site runs (but which accounts for a tiny fraction of
the traffic), this has gone to 1% hitrate, 99% hit_for_pass. Headers
being sent out suggest caching is still behaving as expected but the shm
tools all report this high hit_for_pass rate. Looking at the number of
objects, there's now nothing but object heads in the store.

Any thoughts on what could be going on here?

-- 
Cheers,
James Harrison