In the project that I am currently onboard, besides Single Sign-On, we have Identity Management in place.
Sun OpenSSO + Sun Identity Manager (aka Oracle OpenSSO + Oracle Waveset)
As OpenSSO is one of the Identity resources, we need to reconcile large number of accounts ( >40,000 in development ) into OpenSSO, but the reconciliation process always fail.
It took us pretty long to discover what is causing - do remember to turn off debugging in OpenSSO.
The debug log IdRepo was too verbose (I turned to message logging in development) and was spending too much time logging, than trying to help in reconciliation.