We have an Exchange 2010 environment with a DAG setup with 2 hosts. We're thinking of enabling Circular Logging and was wondering if there's any downside to this? From my perspective: 1) The chances of both servers going down will be slim, so the logs won't be used for DR purposes. 2) Circular Logging will free up 400-500 GB of space 3) If our backups fails and the logs doesn't get truncated, we won't have to worry about it stopping Exchange from functioning Are there any major downside or pitfalls of enabling circular logging in a DAG? The only other question is that since the DAG is based around log shipping and replaying, I would assume that there's a mechanism in place to prevent the logs from being overwritten until it's been copied/replayed into the passive copy?

similar question as yours and some excellent answers http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/a01579af-8cdc-40d3-aef4-b5f569833553

I would assume that there's a mechanism in place to prevent the logs from being overwritten until it's been copied/replayed into the passive copy? This is correct.Paul Cunningham (MCITP) Blog: Exchange Server Pro Book: Exchange Server 2003 to 2010 Migration Guide

Hi Pham0329, Quote "We're thinking of enabling Circular Logging and was wondering if there's any downside to this" Why not, you can use circular logging in DAG model, this is one of the accepted solution when we remove requirement of VSS backup in DAG model. Only the thing is you have to define LAG copy interval value in DR DAG server so in case of DR you will have logs a DR site. some org use it and some not as they have to keep backup for long retention time, So it's up to your managment decesion. Some more information: http://www.msexchange.org/articles_tutorials/exchange-server-2010/high-availability-recovery/eliminating-traditional-backups-using-native-exchange-2010-functionality-part4.html Log Truncation without Backups : http://technet.microsoft.com/en-us/library/dd876874.aspxAnil

similar question as yours and some excellent answers http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/a01579af-8cdc-40d3-aef4-b5f569833553