Hello everyone,

I was looking into event log to try to understand why publishing stops working in one of Umbraco web farms when I noticed this:

 1. It happens a few times that next exception is thrown:

An unhandled exception occurred and the process was terminated.

Application ID: DefaultDomain

Process ID: 4772

Exception: System.Runtime.Serialization.SerializationException

Message: Type 'umbraco.DataLayer.SqlHelperException' in Assembly 'umbraco.DataLayer, Version=0.3.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

StackTrace:    at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter)
   at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck)
   at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck)
   at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.SerializeObject(Object obj, MemoryStream stm)
   at System.AppDomain.Serialize(Object o)
   at System.AppDomain.MarshalObject(Object o)

 2. That exception is followed by:

A process serving application pool 'XXX' suffered a fatal communication error with the Windows Process Activation Service. The process id was '4772'. The data field contains the error number.

 3. At the end application pool stops with next message:

Application pool 'XXX' is being automatically disabled due to a series of failures in the process(es) serving that application pool.

Did anyone have problems like this?

This all happens in a load balanced environment with four web servers hosting Umbraco and one DB server.

Regards,
Sasa