In the "Settings and Diagnostics" policy of the MSMS there is a setting for "Maximum number of old DATs" which has been set to 3 in our environment. It appears that while this works for removing old DATs with standard naming convention in the "bin\DATs" directory, it ignores DAT folders if extra.dats have been rolled out.
The product appears to append a number to the end of the DAT file when an extra.dat has been checked in and combined (eg. 6382.0000-1) which can cause disruptions with how DATs are handled.
I have seen a similar issues with my MSDW 7.5 instances. For these installs I can utilise a scheduled windows task of "PurgeOldDefinitions.exe" (located in the "Security for Domino\bin" directory with an argument of 2 to keep this at a manageable level (KB66611) - though I have noted that there is not a similar program in the "bin" directory for MSMS for use.
Below is a screen shot of one of my Sharepoint servers with the large amounts of DATs with the local policy for Dat retention also shown.
I have a support call logged for this already, but was wondering whether anyone else experiences this issue and has a solution / work around?