Every day the scheduler shuts down (several times it seems) and I have no idea why.

The times are always different and I can't tell what event could be causing this. There are no events prior to the shutdown/stopping of the scheduler to give any clues.

The messages are just:

My scheduled items are:

	Type	Enabled	Frequency	Retry Time Lapse	Next Start
	DotNetNuke.Entities.Users.PurgeUsersOnline, DOTNETNUKE		Every 5 Minutes	Every 15 Minutes		History
	DotNetNuke.Services.Log.SiteLog.PurgeSiteLog, DOTNETNUKE		Every 1 Day	Every 2 Hours	01/11/2008 09:57:43	History
	DotNetNuke.Services.Scheduling.PurgeScheduleHistory, DOTNETNUKE		Every 1 Day	Every 2 Hours		History
	DotNetNuke.Services.Log.EventLog.PurgeLogBuffer, DOTNETNUKE		Every 30 Minutes	Every 2 Hours	31/10/2008 19:28:51	History
	DotNetNuke.Services.Log.EventLog.SendLogNotifications, DOTNETNUKE		Every 4 Hours	Every 4 Hours		History
	DotNetNuke.Services.Search.SearchEngineScheduler, DOTNETNUKE		Every 3 Hours	Every 12 Hours	31/10/2008 21:57:59	History
	DotNetNuke.Modules.Admin.ResourceInstaller.InstallResources, DOTNETNUKE		Every 12 Hours	Every 12 Hours		History
	DotNetNuke.Services.FileSystem.SynchronizeFileSystem, DOTNETNUKE		Every 1 Hour	Every 2 Hours		History
	DotNetNuke.Services.Cache.PurgeCache, DOTNETNUKE		Every 2 Hours	Every 1 Hour	31/10/2008 19:58:01	History
	DotNetNuke.Modules.Events.EventNotification, DotNetNuke.Modules.Events		Every 4 Hours	Every 4 Hours	31/10/2008 21:58:01	History
	OnyakTech.NukeAlert.Scheduler, OnyakTech.NukeAlert		Every 8 Hours	Every 2 Hours	01/11/2008 01:57:49	History
	DotNetNuke.Modules.Forum.StartEmailQueuedTasks, DotNetNuke.Modules.Forum		Every 15 Minutes	Every 1 Hour	31/10/2008 19:28:52	History
	DotNetNuke.Modules.Forum.CleanupEmailQueuedTasks, DotNetNuke.Modules.Forum		Every 1 Day	Every 1 Day	01/11/2008 09:57:43	History
	OnyakTech.NukeAlert.Scheduler,OnyakTech.NukeAlert		Every 1 Day	Every 20 Minutes		History
	Onyak.SigmaPro.EmailViewer.Scheduler,Onyak.SigmaPro.EmailViewer		Every 30 Minutes	Every 5 Minutes		History
	CATALooK.RecurringBilling, CATALooKStore		Every 1 Day	Every 1 Hour	01/11/2008 08:56:23	History

Not sure if anything's not right there.

And the Host settings are:

Scheduler Mode: The Timer Method maintains a separate thread to execute scheduled tasks while the worker process is alive. Alternatively, the Request Method executes tasks when HTTP Requests are made. You can also disable the scheduler by selecting Disabled.
Enable Event Log Buffer? Checking this will cause log entries to be logged to memory and then purged regularly to the data store. Unchecking it will cause log entries to be written immediately.

Is anything else needed?  Any clues as to how I can resolve this?

Many thanks

David

Thanks Sebastian

I hadn't realised this was normal behaviour. So the busier a site gets, the less likely and less often it will stop?  And this is why people look for the 'keepalive' type service?

Cheers

David