My 2c worth.
Seriously consider separating the OS and data onto different drives. The install and update was a fairly quick process, backing and restoring the data was painful and I had about 1TB of data.
I did a server upgrade at the same time. Due to the time to backup data I decided to leave my SME9 running until I had my new sever online. And I wanted to reuse the drives in my SME9 which was set up with raid 1/2 drives only. So I had to migrate my sme9 to another drive, recover the drives, build a new sme10 and restore data.
Pretty much used up a week as my backups (tried USB(old hardware only supported usb2), nfs, aoe, took best part of a day for a backup then another day for a restore) with hindsight if adding another drive to the server had been an option then I'd have used that.
Given that I only do a server upgrade every 4-5 years
it isn't the end of the world but I'm heading down the path of an ~120GB ssd for the operating system and two rust drives in raid 1 for data mounted at /home/e-smith/files/shares (or ibays) depending upon where you keep your data.
Any upgrade or OS rebuild should just require a relatively quick process as the main data drives would be untouched. I believe that there is a few other install out there with this setup. ymmv