ArchiveLogs and Transaction Volumes

Do you monitor ArchiveLog volumes ? I use ArchiveLog generation statistics as
a measure of Transaction Volume. With automated scripts comparing recent hourly
ArchiveLog rates against historical rates (eg hourly rate in the last 6 hours vis-a-vis
hourly rate in the preceding 36 hours ; hourly rate in the last 24 hours vis-a-vis
hourly rate in the preceding 72 hous), I hope to be able to capture spikes in
transaction volumes early.
Recently, we had a database ArchiveLog volumes go up by 20% in two weeks
and another 25% in the next two weeks -- thus by 50% in 1 month.
Systems and Storage were getting ready to provide more disk space for the
ArchiveLogs filesystem while I talked to the application team. There had
been some configuration changes requested by the users and, unbeknown to
the application administrators, Transaction Volumes surged by 50%.
When I asked them about the surges, they were very quick to identify the
cause of the surge.

Fortunately, there are a few {but not enough} application teams that are aware
of what archivelogs are and what they indicate -- a quick and ready measure
of transaction volumes.