Xserve 10.5.8 upgrade to OS X Yosemite with attached Xserve RAID

I have a Xserve running on 10.5.8 and I'm being asked to upgrade the server to OS X Yosemite. Can I get confirmation that these are the steps that I should follow to perform this upgrade?

Upgrade Leopard (10.5.8) to Snow Leopard (10.6). Upgrade to the latest version of Snow Leopard through App Store to 10.6.8. Go to OS X Yosemite page to download Yosemite.

Is this a supported in-place upgrade path? Can I do this upgrade without having to refomat or wipe the hard drive? I also have a Xserve Raid device attached to this server used to store shared files. Should I be concerned about that device during/after the upgrade process?

I apologize if these questions seem silly. I've never managed or administered a Mac server before and want to make sure I'm not doing anything wrong or overlook any details.