A method performed by a coordinator node comprising: accessing a storage device providing a local Level 3, L3, cache local to the coordinator node; connecting to a Level 2, L2, cache storage endpoint over a first network connection; connecting to remote cloud storage over a second network connection; the first and second network connections such that a physical distance between the L3 cache and the L2 cache storage endpoint is shorter than a physical distance for the L3 cache to the cloud storage; characterized by the further steps of: responding to a block write request from the L2 cache storage endpoint as a write back cache, by acknowledging the block write request to the L2 cache storage endpoint within 10 microseconds (μs) or less, even if a data block associated with the write request is not presently stored in the local L3 cache; storing the data block included with the write request and block-related metadata in the local L3 cache before forwarding the data block associated with the write request and the block-related metadata to the cloud storage; maintaining a global logical block address, LBA, metadata map at the coordinator node, local to the L3 cache; and distributing the global LBA metadata map to the L2 storage endpoint and to the cloud storage. accessing a storage device providing a local Level 3, L3, cache local to the coordinator node; connecting to a Level 2, L2, cache storage endpoint over a first network connection; connecting to remote cloud storage over a second network connection; the first and second network connections such that a physical distance between the L3 cache and the L2 cache storage endpoint is shorter than a physical distance for the L3 cache to the cloud storage; characterized by the further steps of: responding to a block write request from the L2 cache storage endpoint as a write back cache, by acknowledging the block write request to the L2 cache storage endpoint within 10 microseconds (μs) or less, even if a data block associated with the write request is not presently stored in the local L3 cache; storing the data block included with the write request and block-related metadata in the local L3 cache before forwarding the data block associated with the write request and the block-related metadata to the cloud storage; maintaining a global logical block address, LBA, metadata map at the coordinator node, local to the L3 cache; and distributing the global LBA metadata map to the L2 storage endpoint and to the cloud storage. responding to a block write request from the L2 cache storage endpoint as a write back cache, by acknowledging the block write request to the L2 cache storage endpoint within 10 microseconds (μs) or less, even if a data block associated with the write request is not presently stored in the local L3 cache; storing the data block included with the write request and block-related metadata in the local L3 cache before forwarding the data block associated with the write request and the block-related metadata to the cloud storage; maintaining a global logical block address, LBA, metadata map at the coordinator node, local to the L3 cache; and distributing the global LBA metadata map to the L2 storage endpoint and to the cloud storage.