Volume Shadow Copy High CPU Usage, Windows Server 2008 R2


I have done some searching around this site and the web in general and have not found any specific information on this particular issue.

I am running a Windows Server 2008 R2 Fileserver on a VM.  It is configured with 1CPU, 4GB RAM and about 700GB of storage.  There is no antivirus or backup software currently installed on the server.  I enabled Volume Shadow Copy configured to take 4 shapshots a day at 2 hour intervals beginning at 11am.  

This all worked great and smooth for a several months then all of a sudden we began getting major slowdowns and intermitent connection failures to the files for 5-15 minutes.  After lots of digging throuogh logs and tweaking I finally narrowed it down to VSS.  Those failures and slowdows perfectly coincide with shadow copy schedule.  When the snapshot process starts it consumes all of my CPU and this disconnects users from their documents and they lose connection to their DFS mapped drives and their computers become extremely slow or unusable, etc. until the snapsop process is completed.  This usually lasts about 5-10 minutes thought the effects to the employees workstations can last up to 20 minutes.

Can anyone tell me if there is a way to stop the process from taking up all my CPU resources during that time, outside of disabling Volume Shadow Copy altogether?  It is necessary for our environment as we need the 2 hr file recovery period.

My next step to try would be allocating another CPU to its resources to see if that makes a difference but i would like to know if there is another solution before I try that.
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How much disk space do you have used?  VSS will use its own section, and depending on your settings, it could be using up your space and having to clear some old snaps to make room.
MeridianInternationalAuthor Commented:
No, I thought that may have been the case but I have plenty of space.  There is 30GB of allocated space for shadow copies and only 9GB of that is currently being used.  The drive currently has 235 GB free space.
MeridianInternationalAuthor Commented:
I decided to try reconfiguring the Shadow copy from scratch and see if that helps.  I disabled it and recreated the schedule.  The first snapshot will run at 11AM EST today so I will see how that goes and post the results then.

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an issue with some previous versions that may have carried over..

Large audit log
Writer time-out errors might also appear during a system-state backup if the audit log is extremely large. It is best to back up or to clean the audit log periodically.
MeridianInternationalAuthor Commented:
The security audit log is capped at 20MB which is where it has been since the server was brought online late last year.   It is set to drop off the oldest logs to maintain that size.  Currently it is at that limit and holds about 14 days worth of data which is shere it has been for several months. Currently between 9/22/11 to today.  This issue just started occuring within the past 2 weeks.

I will try your suggestion if my previous rebuild does not work at 11am.
MeridianInternationalAuthor Commented:
I monitored the system today during the scheduled times of the issues after disabling, reconfiguring and re-enabling the volume shadow copy.  The High CPU utilization time period has dropped significantly to about 2-5 seconds instead of the 5-10 minute period.  I have not gotten any complaints from the network users so I believe that the issue may be resolved so far. I still have the 5-5:30pm window to monitor.  I will also monitor this for one more day to make sure that the problem does not return.  I will then consider this issue as resolved.
MeridianInternationalAuthor Commented:
I have not had any more complaints from users about the slowness or freezing since Tuesday and as stated above the CPU Usage is down to seconds now.  I would consider this issue resolved.
MeridianInternationalAuthor Commented:
I decided on a course of action not supplied by the expert which resulted in the resolution of the issue.
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Windows Server 2008

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