i'll try with the 1st question only this time (I guess second was already answered)
"As you are well aware SMO doesn't handle the Obsolete archive logs."
That's not true, actually SMO takes snapshots of archive log location(s?). You have to have archived redo logs as part of your online backup of Oracle, becasue without those you are not able to recover to some consistent point during restore. Technically it means that SMO/SMSAP during restore connects to the snapshot of archive log volume and applies those redo logs to the recovered instance SINCE the starting hot-backup.. so need (per single SMO backup) only a few archive logs to actually bring Oracle to the state of the backup (it needs to apply those logs to bring Oracle to consistent/non-hot-backup mode so that it acutally is able to open). The best way to save space would be:
1) delete obsolete archivelogs
2a) run hot-backup via SMO(take the snapshots)
2b) actually SMO will cause a several log switches
2c) and take snapshot of Oracle archive log location
The question is about synchronizinng 1+2a+2b+2c. In my opinion the best ways are: 1) SMO+RMAN+cronjob or 2) manual cronjob script (calling smo manually) 3) find a way of running some command from SMO before taking hot-backup (i don't know of any scripting entry before doing hot-backup, other than PM/DFM pre-backup script, but you didn't state anything about PM so i guess you are not using it)
NOTE: you cannot have just simple cronjob that is going to remove archived redo logs, because this cronjob might remove some files during SMO backup run and thus backups would fail.
Hope that helps.
Message was edited by: jakub.wartak