I used OS X Server in 2008. It had major quality issues that seemed to only get worse with subsequent releases. Several advertised features accessible from the UI didn't work or straight-up broke things. I doubt Jobs paid much attention to it.
Why would you think he wasn't? Many anecdotes mention him micromanaging minute details, and many of the things he mentions in keynotes are highly technical as well as low-level.
http://www.zdnet.com/article/apple-announces-zfs-on-snow-leo...