Hi,

we installed Umbraco 7.2.1 following "Traditional load balancing " documentation.

1 backoffice, 3 frontend and 1 database server. The loading balancig is managed by hardware and a task syncronizes all files (except App_Data) every 5 minutes.

From one year to now everything was fine, the other day editors published some news during high traffic and all three frontend servers had cpu and RAM at 100%. We had to turn off the portal. The umbraco.config was 20MB.

These are the first error logs:

frontend 2016-07-29 10:49:25,049 [8] ERROR Umbraco.Web.Scheduling.ScheduledPublishing - [Thread 153] An error occurred with the scheduled publishing System.Net.WebException: The operation has timed out at System.Net.WebClient.UploadDataInternal(Uri address, String method, Byte[] data, WebRequest& request) at System.Net.WebClient.UploadString(Uri address, String method, String data) at Umbraco.Web.Scheduling.ScheduledPublishing.Run()

2016-07-29 10:52:18,615 [8] ERROR Umbraco.Web.Scheduling.KeepAlive - [Thread 66] Error in ping System.Net.WebException: The request was aborted: The operation has timed out. at System.Net.WebClient.DownloadDataInternal(Uri address, WebRequest& request) at System.Net.WebClient.DownloadString(Uri address) at Umbraco.Web.Scheduling.KeepAlive.Start(ApplicationContext appContext, IUmbracoSettingsSection settings)

backoffice 2016-07-29 11:01:28,718 [7] ERROR Umbraco.Web.BatchedServerMessenger - [Thread 32] Error refreshing a node in the distributed list, URI attempted: invalid url (responseUri null) System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult) --- End of inner exception stack trace --- at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult) at System.Net.Connection.ReadCallback(IAsyncResult asyncResult) --- End of inner exception stack trace --- at System.Web.Services.Protocols.WebClientProtocol.EndSend(IAsyncResult asyncResult, Object& internalAsyncState, Stream& responseStream) at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult) at Umbraco.Web.BatchedServerMessenger.SendMessages(IEnumerable`1 messages)

any idea?

Thank you very much

Marco