Google appengine datastore alternative?

I'm using Google AppEngine with build-in datastore. But, I want move all datastore to my new VPS.

I'll use Apache Cassandra. How to move from GAE Datastore to Apache Cassandra?

My guess is you're looking at a tool such as the bulk loader/downloader:

http://code.google.com/appengine/docs/python/tools/uploadingdata.html

You'll want to export all your data into CSV, then write a script to import this into any new format you want.

You can not use the bulk downloader if you are using the "High Replication" datastore. You can use a manual aproach such as listing all your entities as dictionaries. You will have a JSON formatted string. By using this you can generate your entities again suitable for your new system.