Database file size - db BI lg Before-Image Cluster Size etc.... 10.2B05

Starting new with a company and working performance issue. Been awhile since I did any DBA stuff. Anyway just some existing db spec:

db size in 12GB on disk
BI size is 13GB on disk
lg size is 7GB on disk - lg born Oct 18 2011
Before-Image Cluster Size: 524288
Before-Image Block Size: 8192

I don't see any BI Truncate lg entries

Online backup only - with the history of the BI file should I expect backup performance issues due to: BI size, BI Cluster size, BI never truncated, all of the above or more?

Also database is accessed via an appserver - clients browsers getting intermittent error 500 during backup and at other time in the day.

Any insight would be helpfufpromon Performance Indicators: promon Performance Indicatorspromon Performance Indicators: promon Performance Indicators