Problem

At work we have an iOS app that is communicating with a windows application. In fact, it communicates to a WAMP (Apache on Windows) server. On the first request, data is being sent, which is then passed to our Windows application. This application creates a PDF report on a network share. This report will then be fetched by the iOS app.

We had a problem though with fetching the content after the process was done creating the PDF. The file was there, but Apache didn’t see it yet, so it returned a 404. We created a workaround by requesting the URL in a for loop to see when the file was available, and then the creation process would end. In the Apache access logs we could see that after retrying for about 10 seconds, the file finally became available to Apache.

Network cache

The webserver is running on a different server as the fileserver. The file is being saved to a location on the file server. So after testing and debugging for a while, we searched how we might improve the performance of the network.

Finally we found this article by Microsoft, which documents some configuration settings that can be set in the registry. I didn’t think this would help, but we tried it anyways.

To my great surprise: it did work! Now the file was already present at the first request that was made by the Apache web server. So our performance increased 10 times.

The settings we added to the registry were:

FileInfoCacheLifetime: set to 1 sec
DirectoryCacheLifetime: set to 1 sec
FileNotFoundCacheLifetime: set to 1 sec

We added this settings on the client machine, so in our case the webserver that is reaching out to the file server. A reboot was not required. The next time we checked, the response was a lot quicker.

So this was a great improvement. We’re not sure yet what the cost of this change is, but since the servers are running on the same virtual platform, I don’t think there will be any downside to this setup. Maybe when you’re on a slow network these settings could make things worse. But for us this really helped.

Hopefully for you too.