Why my Exchange Server 2007 transaction log gets full

I'm having problem in one of the partition of the Exchange Server 2007 SP 2 transaction log, it is installed on my Windows Server 2008 with the configuration as CCR.

In one of the storage group, the transaction log partition goes down quickly to low ([from 30 GB into 0 KB in just over the weekend) when the backup missed just one day thus rendering the whole mailbox on that Storage group inaccessible.

Is there any way to identify what could be the root cause of this problem and how to rectify this ?

Any comments and suggestion would be greatly appreciated.

Thanks.

This is correct - A Backup will automatically clear your logs for you. I also have a CCR environment - The transaction logs are exactly what they're called. Every "transaction" or change regarding mail (logs are like your instructions to your database that say "here are your changes!") - need to be "written" to your Storage Group Databases. First, your Active Node (in the cluster) will be creating the initial transaction logs on your server. The storage group databases (.edb files) are then "seeded" to your Passive Node in your network. This initial seed is usually done at the time your cluster is created - or if you rebuild / repair a storage group database...Once seeded, the only thing that moves between the nodes are the transaction logs. The logs are created from the active node - and are then sent over to the passive node to "update" the passive node's .edb files or Storage group databases. If your Active node cannot pass those logs to the passive node, they can fill up very fast. Basically, do a back up - but another place to check would be network connections (between the two nodes or File Share Witness Communication. Also check your Fail-Over Cluster logs / System Application Logs on the nodes - these will both be FULL of useful information as to why or where there could be problems.

Exchange transaction-logs only get cleared after a successful backup. In your case, I would examine your backup system's backup logs for clues as to why the backups are failing.