I think this is your issue, if it is it is fixed in sp2 but there are workarounds.
http://seer.entsupport.symantec.com/docs/323103.htm
The 'Items Archived per Hour' report will not display items properly if the archiving start time spans days between local time and GMT.
Details:
This issue can occur in the following scenario:
Archiving schedule begins at 9 PM Eastern Standard Time (EST) which is 1 AM Greenwich Mean Time (GMT). The times are stored in GMT in the database, but then translated to local time to display in the report. When the start time of the schedule is on one day in local time, but a different day in GMT then the report will contain zeros during the times when items were actually archived.
Workaround 1
By default, the report is set to run for the Specific Day. Changing the report to run for Week beginning instead of Specific Day will show the correct numbers for archiving.
1. Go to the Report page and then Home > Symantec EnterpriseVault > en-US > Operation Reports > and click Items Archived per Hour.
2. Change the Period from Specific Day to Week beginning.
3. Set the Day value to one day prior to the current day.
4. Click View Report to run the report.
Workaround 2
Use the following query in a SQL query window to determine the amount of items that have been archived. These times are stored in GMT so the date and times must be replaced with the appropriate GMT time in which the item would have been archived. The following query will show what was archived between 1 - 2 AM GMT, which is 9 - 10 PM EST (local time of the EV server).
Select count(*),min(archiveddate),max(archiveddate)
from saveset where archiveddate >'20090414 01:00:00:0'
and archiveddate < '20090414 02:00:00:0'
Symantec Corporation has acknowledged that the above-mentioned issue is present in the current version(s) of the product(s) mentioned at the end of this article. Symantec Corporation is committed to product quality and satisfied customers.
This issue is currently under investigation by Symantec Corporation. Pending the outcome of the investigation, this issue may be resolved by way of a patch or hotfix in current or future revisions of the software. However, this particular issue is not currently scheduled for any release. If you feel this issue has a direct business impact for you and your continued use of the product, please contact your Symantec Sales representative or the Symantec Sales group to discuss these concerns. For information on how to contact Symantec Sales, please see http://www.symantec.com
Please be sure to refer back to this document periodically as any changes to the status of the issue will be reflected here.
