Increasing DTC log file size

Recently we were looking at changing Distributed Transaction Coordinator (DTC)’s log file size and learnt a few things.

By default, the Maximum log file size is 64 MB. For general scenarios, one should not need more than that. But if you have a reason to increase the log file size past 64 MB, you can push this up to 512 MB provided you have a certain registry entry – MaxLogSize under MSDTC registry key.

For standalone servers, this is under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC .

For Clustered DTC, it is at HKEY_LOCAL_MACHINE\Cluster\Resources\<ResID>\MSDTCPRIVATE\MSDTC

Create a DWORD entry MaxLogSize and set it to 512 (decimal)


In the absence of the registry entry, however, when you try to set it to any value > 64MB using the COM+ MMC, you will get the following error message which could be confusing.

“Invalid log size. The log file must be between 1Mb and 512Mb in size”

Now, when you enter …say 90, and the error message asks you to keep it below 512, what do we do?

Firstly, make sure the new log file size [i.e, 90] is indeed less than 512 J

Then, create the registry key as described above.


 We do note that the error message is confusing and this will be addressed in next versions.