Re: [LSF/MM TOPIC] Remote access to pmem on storage targets

["Atchley, Scott" <atchleyes-1Heg1YXhbW8@public.gmane.org>]

> On Jan 25, 2016, at 4:19 PM, Chuck Lever <chuck.lever@oracle.com> wrote:
> 
> I'd like to propose a discussion of how to take advantage of
> persistent memory in network-attached storage scenarios.
> 
> RDMA runs on high speed network fabrics and offloads data
> transfer from host CPUs. Thus it is a good match to the
> performance characteristics of persistent memory.
> 
> Today Linux supports iSER, SRP, and NFS/RDMA on RDMA
> fabrics. What kind of changes are needed in the Linux I/O
> stack (in particular, storage targets) and in these storage
> protocols to get the most benefit from ultra-low latency
> storage?
> 
> There have been recent proposals about how storage protocols
> and implementations might need to change (eg. Tom Talpey's
> SNIA proposals for changing to a push data transfer model,
> Sagi's proposal to utilize DAX under the NFS/RDMA server,
> and my proposal for a new pNFS layout to drive RDMA data
> transfer directly).
> 
> The outcome of the discussion would be to understand what
> people are working on now and what is the desired
> architectural approach in order to determine where storage
> developers should be focused.
> 
> This could be either a BoF or a session during the main
> tracks. There is sure to be a narrow segment of each
> track's attendees that would have interest in this topic.
> 
> --
> Chuck Lever

Chuck,

One difference on targets is that some NVM/persistent memory may be byte-addressable while other NVM is only block addressable.

Another difference is that NVMe-over-Fabrics will allow remote access of the target’s NVMe devices using the NVMe API.

Scott