Exchange Double Size Incrementals

[mkaec]

That large incremental backups can be produced from Exchange (and SQL) servers has been discussed before. That's just the nature of block based backup of highly transactional systems.

When I first put our Exchange server into Veeam B&R, I had a great idea. Traditional Exchange backup involves backing up the databases on a full backup and then backing up the logs on incremental backups. But, Veeam B&R backs up the changed blocks in the databases during incremental backups in addition to the log files. So, I thought I could save some repository space by excluding the log files. That was a reasonable thought. If you've got an up-to-date EDB, you don't really need the log files.

When I went to test Veeam Explorer, I got an error that the logs were missing. It seems restore needs the logs if the EDB was live when it was backed up. That's because there's no guarantee that 100% of the log files had been played into the EDB when the backup was taken.

But it is a bummer. I'm effectively backing up the same data twice now. Once from the database and a second time from the log files.

[Regnor]

In order to get a consistent backup both the EDB and logs need to be backed up and restored. Without the logs and checkpoint-file the EDB will come up in "dirty shutdown"; if you restore your exchange or the EDB you'll have to "repair" the database with eseutil.

You could activate circular logging if you have only limited backup space, which I wouldn't recommend.
If your EDB get's damaged during the day, you won't be able to recover it from backup + current logs.

[mkaec]

You are right that the logs are required. It's the EDB blocks that are actually unnecessary when it comes to incremental backups. I do understand why one would choose to design it like this. I wonder if there's an opportunity for inline dedupe to handle this as a special case.

[billcouper]

also worth knowing that if you repair the database with eseutil you will have an unsupported configuration, microsoft will not provide support for your exchange environment... the resolution is to create a new database, migrate all the data, and delete the old database