A method of operating a daisy-chained device-mirroring architecture (where
such an architecture may include a storage node N configured to mirror
data on an entity representing node N-1, a storage node N+1
daisy-chain-coupled via a first main link to, and configured to mirror
data on, the node N, and a storage node N+2 daisy-chain-coupled via a
second main link to, and configured to mirror data on, the node N+1, each
of the nodes N and N+1 being operable under normal circumstances to
forward writes received thereby to the nodes N+1 and N+2 via the first
and second main links, respectively), where such a method may include:
tracking, at the node N, acknowledgments by the node N+1 and by the node
N+2 of writes that the node N has forwarded.