Research Agenda on Efficient and Robust Datapath Yingping Lu

OSD Data Transmission Requirements Direct delivery from object device – Direct transmission between initiator and target device – This is the critical data path Secure delivery – No security channel is assumed, encryption of transmitted object is necessary – Object device exposed to network access QoS requirement – Object may have specific QoS requirement (bw, latency) Mobile client – Client may be intermittent – Error can occur during transmission

Approaches Robust Secure RDMA in End System (LAN) – RDMA / OSD in OSD device – Incorporate security in RDMA mechanism – Incorporate robustness in RDMA mechanism Adaptive Transport QoS Control – Tailor the data transmission based on the underlying network behavior Proper data delivery of wireless communication – radio resource management

OSD/Secure RDMA This is a ULP-based RDMA – The RDMA is tightly integrated with OSD protocol Leverage RDMA over TCP/IP – Extend the communication to IP network OSD device initiate RDMA requests Security-enabled RDMA – The underlying transport support security QoS support – Virtual Lane-type mechanism to provide QoS support

OSD/Secure RDMA Architecture OSD Client OSD controller OSD VIPL Object Manager Buffers Disk Driver NIC VI NIC driver OSD Device Application OSD VIPL Buffers NIC VI NIC driver IP network

Protocol Stacks OSD/RDMA maps OSD to RDMA DDP provide the direct data placement The underlying transport can be either SCTP or MPA with TCP. IPSec is used as security protocol (object encryption) SCTP DDP OSD/RDMA OSD Protocol TCP MPA IP/IPSec Intelligent NIC OSD Consumer OSD VIPL Consumer

Research Issues Functionality distribution among regional manager and intelligent device – What are the reasonable assumptions about two components? – Under such assumption, what is the best way to partition the functions? Statically or dynamically? – What’s the implications of the partition to the network, storage device, supporting software?

Research Issues RDMA over OSD – Characterize main operations and requirements of OSD protocol Common operations Customized operations by the object creator – Characterize the capability of OSD device or OSD subsystem – Study the implication of these requirements to RDMA design in OSD device

RDMA/OSD Issues System Architecture of OSD Device – The role of individual object – The role of supporting system – The interaction between the supporting system and user object – Two existing types, what’s our position? Passive data (normal file system) Active objects (COM objects, EJB objects)

RDMA/OSD Multiple Protocol processing in RDMA – ULP Application OSD iSCSI – LLP (TOE) TCP or SCTP? IP Ethernet – Different level has different header and message size, how to adding/removing the header, segmentation/desegmentation without incurring multiple data copies?

RDMA/OSD Data sharing in RDMA – Different clients may access the same object, thus has the data sharing requirement. – Who provide data sharing? Object itself or device subsystem? – How to provide data sharing in RDMA/OSD? RDMA is a one-to-one communication between server and client How to manage the registered buffer? How to incorporate the flow control?

RDMA/OSD Security implication – How to prevent malicious attack? – How to incorporate the security measure with RDMA? IP level (IPSec)? Upper level? Object level?

RDMA / OSD QoS for OSD session – QoS attributes? – QoS mechanism at the OSD device – QoS hint exploitation? – QoS functionality partition: Object Device? – How to collect proper information for each stream and adjust the transmission based on underlying network behavior

Failure recovery Failure: – Disk device failure – A TCP connection break – Client crash

Research Focus Get familiar with two projects and its code: – Intel iSCSI/OSD – Lustre Focus: – OSD System Architecture – Upper level OSD protocol design issues – Lower level protocol design issues (TOE)