We have some very simple integration components that are used to transport flat files, they do not interpret the contents, simply package them up into a string, and then unpack them at the other end, anyone got any tips on hoe to improve performance, a 5MB file takes almost 5 minutes to publish, and the end to end process takes 15 minutes, the equivalent ftp took about 40 seconds

Why not just use the FTP server? It sounds like you’re not doing anything that the Broker or the IO Adapter are designed for (transporting large files, ala FTP, is not a forte of ES or IS) so you might as well use the tool that does this sort of activity well. Or is there more to your integration than just moving raw data?

Marek,

If speed through the broker is important then try setting the document type to Volatile. This should bring down the elapsed time to be similar to that of FTP.
I guess that you have already increased the size of memory available to the IO adapter.

If you need to guarantee the document, then a suitable workaround could be developed such as another (small) document that indicates that the big document is to follow immediately.