In this blog entry it says that you can install Cassandra in any OS, however I wonder if there is a preference between Windows and Linux. Moreover, if a customer decides to install Cassandra in Linux, does Skyline provides support as usual? Or is support limited to Windows OS?
Skyline will provide support if there are issues on their system even when their DB is running on Linux environments. Skyline uses by default Windows machines to run Cassandra (as Cassandra is installed on the same server as DataMiner).
If you have a heavily loaded system on DB level (e.g. a lot of trending or alarming) you want to run Cassandra on a separate server to prevent Cassandra from impacting your DataMiner services. When you want to install Cassandra on a separate server you can choose on what operating system you install your Cassandra node. It is up to the user to decide if they prefer Linux or Windows.