I've never had formal IT experience but I've always been someone interested in technology. I basically grew up assembling computers for fun and using them for lots of different personal projects. In terms of library experience, I did have some directly related experience from my paraprofessional jobs and archival internships (mostly using PastPerfect and ArchivesSpace). I also had a large personal project (website, digital map, and CMS / database) that I built to showcase my skills. I started it in library school but it is something I'm continuing to work on even now.

So yes, I had some relevant experience and just a general background using technology. But I'm not someone who can code, and I never intend to become a programmer. Some systems jobs seem too overwhelming, even for me. But there are others that I think are more manageable, like mine. And library school classes, especially org of info and metadata should suffice for someone to do what I'm doing now.

I don't think an IT background is necessary but it could help in certain roles. You could also consider taking IT courses and see if you can substitute them for library science courses instead. I took a GIS class to help me with my project.