I think most modern disks just never design with sudden power-lost safety in mind (some enterprise disks do have such guarantee, by adding a battery or a capaci

I think most modern disks just never design with sudden power-lost safety in mind (some enterprise disks do have such guarantee, by adding a battery or a capacitor to buy time for properly flush the cache to disk). A disk AND an UPS is probably the minimal combination that you can guarantee that your data is actually persisted.