The main issue however is not the hash's strength, but the fact that once pre-computed, I'm able to use preimages on **every Ceph cluster out there**. (As the hash functions's output is a deterministic function of the object's name only) I agree in that the general issue is inherent in hash-placement systems. But what I don't agree with is the following: Why do I have to be able to calculate my object's placement for **every Ceph cluster** out there? Why does it not suffice for me to be able to calculate the placement only for the cluster I'm currently accessing? >From a logical standpoint it seems reasonable. Why then, are we not able to constrain the placement calculation in that regard? If the placement is bound to a specific cluster it should suffice to derive e.g. a key for SipHash based on cluster specifics. Is this doable from an implementation point of view? Note: I only did this as a proof-of-concept for the object store. Think about the implications, if you're able to do this e.g. for every RadosGW out there and servies using RadosGW. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
