How to use Aerospike in Cloud Datacenter for Update Operations?

How to use Aerospike in Cloud Datacenter like AWS ?

I understand Aerospike provide sub-milliseond read latency as its highly optimised for Flash Storage. But AWS has issue of emphemeral storage. I understand Aerospike provides Shadow Device feature for it where

  1. reads done from SSD
  2. writes done(async) to SSD and NAS(EBS)

But even if writes done async to NAS, doesnt NAS creates bottleneck for write operations i.e. if EBS offers throughput of 200MBps then User can not write at rate higher than 200MBps. Plus due to write amplification of 2 and Replication factor of 2, User throughput can’t exceed beyond 200MBps / (2 * 2) = 50MBps … Assuming record of size 10K, it translates to 5K TPS (Update operations) i.e. for throughput of 100K TPS I need to deploy 20 NAS.

Is there any way I can avoid “update” operations bottleneck from NAS ?