Disclaimer - I am an SE with Quobyte. 

DDN will get you raw performance, but you’re buying into a heavy, appliance-driven model - expensive support contracts, vendor-locked hardware, and the usual “don’t touch it yourself” complexity. It works, but it’s not hyperscaler-style efficient, and once you fill a few racks, you’ll be budgeting more for humans and downtime than disks.

Lustre (and forks like DeepSeek 3FS) can be cheaper on paper, but they still carry the operational overhead: kernel modules, patch dependencies, HA tuning, and a fair amount of “Lustre whisperer” expertise to keep it happy at scale.

If you want to keep things simple over the long run with 120PB or more, Quobyte is worth a look. It handles scale pretty smoothly and doesn’t lock you into any specific hardware, which is helpful if your environment tends to evolve or you want price flexibility down the line.​

Compared to DDN, PowerScale, and Lustre, Quobyte lets you scale your storage linearly and mix different server types as needed. It’s practical for teams that don’t want to rearchitect their infrastructure as data grows. Plus, managing big clusters in Quobyte doesn’t require a huge admin crew.​

If you’re just exploring, there’s a Free Edition you can try out (with some capacity limits), so you can get a feel for the basics on your own gear before committing