Why does STORE.EXE use so much memory

I am asked all the time why the STORE.EXE uses so much memory? Is it a memory leak? A bug? A configuration problem? No, none of these. It is a 'feature'.

The STORE.EXE is the Exchange executable that runs the ESE database engine, handles database connections, and caching. Naturally, it wants as much memory as possible. The specific feature that allocates all the RAM is called DBA (dynamic buffer allocation). There is a pretty good KB article that describes memory optimization for Exchange 2003, but the DBA feature applies to all versions since Exchange 5.5.

KB 815372: How to optimize memory usage in Exchange Server 2003

If you are running Exchange 2003 SP1, though, see the SP1 release notes for additional information on memory tuning.

It is not uncommon for STORE.EXE to allocate up to 80% of the available RAM in an Exchange server. The only thing to worry about is if Exchange server's available physical memory starts to drop below about 5 - 10% of the total physical memory. Then you have a memory shortage due to insufficient RAM, a memory leak, or other bug.

Keywords: Exchange STORE.EXE RAM virtual memory 5.5 2000 2003 optimization