Domain Controller CPU Spike - Due to system logs

Question

Hi all,
Wondering if anybody out there is having the same issue as me, and if they have found a solution to it.
A number of our Domain Controllers 2008 forest on physical and virtual 2008r2 servers with full patches were having a heart rhythm spike in the CPU. Depending on the number of CPU available to the DC would depend on the percentage CPU spike.
We have found the reason for the spike and it is due to a capping in place within the system logs. When the logs hit the cap and a new log goes to write it first has to remove an old log from the system and thus sends the cpu sky high.
Does anyone know why this is only happening now as the capping has been in place for a number of years now with no issues present until recently.
Is there a perminant fix that I can put in place, instead of saving off the logs and then deleting as part of monthly maintenance before they fill up to the max and cause the spiking to happen again. 
has anyone setup the system logs to fill on the separate drive/partition and scripted a save copy and delete every 90 days for example.  
Maybe someone has seen this and come up with a smarter way of dealing with it, id love to hear from you.
cheers
Calv 

Answer 1

To remove the system event log, please refer to the article below:
http://technet.microsoft.com/en-us/library/hh849786.aspx-EventLog
We can also overwrite older events  or  clear a log of its contents when it reaches the initial maximum of size of a log.
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To specify log size and overwrite options, follow these steps:
Click Start, and then click Control Panel.  Click
Performance and Maintenance, then click Administrative Tools, and then double-click
Computer Management.  Or, open the MMC containing the Event Viewer snap-in.
In the console tree, expand Event Viewer, and then right-click the log in which you want to set size and overwrite options.
Under Log size, type the size that you want in the Maximum log size box.
Under When maximum log size is reached, click the overwrite option that you want.
If you want to clear the log contents, click Clear Log.
Click OK.
Hope it's helpful.
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