no such thing
as fast access to primary data in the cloud, unless the thing accessing that data lives in the same cloud. Even then your not likely to get it fast (relative to something like Avere's technology)
In fact the whole concept is totally stupid, you better hope for 100% cache hit rate because the moment you have to go to the cloud to get some of that data your stuff is going to come to a grinding halt. Latencies will go from microseconds(I assume) on the Avere SSD cache to minutes or even hours when data is pulled in from the cloud. Meanwhile users will be confused why everything just came to a grinding halt, it's not as if your NFS or CIFS system can present a message to the client(that I know of) saying "please wait while we get the data for you ...................................."
It's not Avere's fault for this latency of course, the latency comes from the distance between the client (Avere) and the cloud, having a fancy tiering system doesn't make network packets go any faster.
Though you could slash efficiency and blow up your bandwidth costs by chunking your data out in lots of pieces and accessing it in parallel, but unless your limiting yourself to very infrequent accesses I suspect the cost of bandwidth will outweigh the cost savings of cloud storage very quickly.
does Avere accelerate writes or only reads? Looks like they do writes as well. Most of those ssd acceleration thingies only accelerate reads.