Converged data center_f_co_e_iscsi_future_storage_networking

1© Copyright 2014 EMC Corporation. All rights reserved.© Copyright 2014 EMC Corporation. All rights reserved.
FCoE, iSCSI AND THE FUTURE OF
STORAGE NETWORKING
David L. Black, Ph.D., Distinguished Engineer
CONVERGED DATA CENTER

Roadmap Information Disclaimer
 EMC makes no representation and undertakes no obligations with
regard to product planning information, anticipated product
characteristics, performance specifications, or anticipated release
dates (collectively, “Roadmap Information”).
 Roadmap Information is provided by EMC as an accommodation to
the recipient solely for purposes of discussion and without intending
to be bound thereby.
 Roadmap information is EMC Restricted Confidential and is provided
under the terms, conditions and restrictions defined in the EMC Non-
Disclosure Agreement in place with your organization.

Agenda
 Network Convergence
 Protocols & Standards
 Server Virtualization
 Solution Evolution
 Conclusion

10Gb Ethernet Converged Data Center
 Maturation of 10 Gigabit Ethernet
– Single network simplifies mobility for virtualization/cloud deployments
 10 Gigabit Ethernet simplifies infrastructure
– Reduces the number of cables and server adapters
– Lowers capital expenditures and administrative costs
– Reduces server power and cooling costs
– Blade servers and server virtualization drive consolidated bandwidth
FCoE and iSCSI both leverage this inflection point
LAN
SANSingle Wire for
Network and Storage
10
GbE

Un-Converged Rack Servers
• Servers connect to LAN, NAS
and iSCSI SAN with NICs
• Servers connect to FC SAN
with HBAs
• Some environments are still
Gigabit Ethernet
• Multiple server adapters,
higher power/ cooling costs
Rack-mount
servers
Ethernet
Fibre Channel
Ethernet LAN
Ethernet
Ethernet
NICs
Storage
Fibre Channel SAN
Fibre
Channel
HBAs
Ethernet
iSCSI SAN
Note: NAS is part of the converged
approach. Everywhere that Ethernet is
used in this presentation, NAS can be
part of the unified storage solution

Agenda
• Network Convergence
• Protocols & Standards
• Server Virtualization
• Solution Evolution
• Conclusion

IP Network
iSCSI Introduction
 Transport storage (SCSI) over standard Ethernet
– Reliability through TCP
 More flexible than FC due to IP routing
– Effectively reaches lower-tier servers than FC
 Good performance
 iSCSI has thrived
– Especially where server, storage, and
network admins are the person
– Example: IaaS Clouds
▪ E.g., OpenStack
Link
IP
TCP
iSCSI
SCSI

iSCSI Introduction (continued)
 Standardized in 2004: IETF RFC 3720
– Stable: No major changes since 2004
– NEW: Consolidated spec (RFC 7143), minor updates (RFC 7144)
▪ Backwards-compatible with existing implementations
 iSCSI Session: One Initiator and one Target
– Multiple TCP connections allowed in a session
 Important iSCSI additions to SCSI
– Immediate and unsolicited data to avoid round trip
– Login phase for connection setup
– Explicit logout for clean teardown

iSCSI Read Example
Optimization: Good
status can be included
with last “Data in” PDU
Command
Complete
Receive
Data
SCSI Read
Command
Initiator Target
Status
Data in PDU
Target
Data in PDU
Data in PDU

iSCSI Write Example
Optimization:
Immediate and/or
unsolicited data
avoids a round trip
Status
Initiator
Ready to
Transmit
Target
SCSI Write
Command
Ready to
Transmit
Command
Complete
Receive
Data
Receive
Data
Data out PDU
Data out PDU
Data out PDU
Data out PDU

CRCEthernet
Header
IP TCP iSCSI
iSCSI Encapsulation
Delivery of iSCSI Protocol Data Unit
(PDU) for SCSI functionality (initiator,
target, data read/write, etc.)
Provides IP routing capability so packets
can find their way through the network
Reliable data transport and delivery (TCP windows,
ACKs, ordering, etc.) Also demux (port numbers)
Provides physical network capability (Cat 6a, MAC, etc.)
Data

FCoE: Another Option for FC
 FC: large and well managed installed base
– Leverage FC expertise / investment
– Other convergence options not incremental for existing FC
 Data Center solution for I/O consolidation
 Leverage Ethernet infrastructure and skill set
FCoE allows an Ethernet-based SAN to be introduced
into an FC-based Data Center
without breaking existing administrative tools and workflows

FCoE Extends FC on a Single Network
Network
Driver
FC
Driver
Converged
Network Adapter
Server sees storage traffic as FC
FC Network
FC Storage
Ethernet
Network
FCoE
Switch
Lossless Ethernet
SAN sees host as FC
Ethernet
FC

FCoE Frames
 FC frames encapsulated in Layer 2 Ethernet frames
– No TCP, Lossless Ethernet (DCB) required
– No IP routing
 1:1 frame encapsulation
– FC frame never segmented across multiple Ethernet frames
 Requires at least Mini Jumbo (2.5k) Ethernet frames
– Max FC payload size: 2180 bytes
– Max FCoE frame size: 2240 bytes
Ethernet
Header
FCoE
Header
FC
Header
FC Payload
CRC
EOF
FCS
FC Frame

FCoE Initialization
• Native FC link: Optical fiber has 2 endpoints (simple)
– Discovery: Who’s at the other end?
– Liveness: Is the other end still there?
• FCoE virtual link: Ethernet LAN or VLAN, 3+ endpoints possible
– Discovery: Choice of FCoE switches
– Liveness: FCoE virtual link may span multiple Ethernet links
• Single link liveness check isn’t enough, where’s the problem?
• FCoE configuration: Do mini jumbo (or larger) frames work?
• FIP: FCoE Initialization Protocol
– Discover endpoints, create and initialize virtual link with FCoE switch
– Mini jumbo frame support: Large frame is part of discovery
– Periodic LKA (Link Keep Alive) messages after initialization
Ethernet is more than a cable

FCoE Switch Discovery
Step 1: FIP Solicitation
FCoE/FC
Switches
DCB Ethernet FC SAN
 Select FCoE VLAN first (pre-config or FIP)
 Multicast Solicitation: Server can discover multiple switches
 Solicitation identifies Server (FC WWN for FCoE CNA)
– CNA = Converged Network Adapter (FCoE analog of HBA)
– Switch chooses servers to respond to (default: respond to all)
Solicitation
Server

FCoE Switch Discovery
Step 2: FIP Advertisement
FCoE/FC
Switches
DCB Ethernet FC SAN
 Advertisement identifies switch
– Multiple switches may respond, advertisement includes priority
– Server chooses FCoE switch by priority (smallest number wins)
 Advertisement padded to max FC frame size: Test mini jumbo frames
Advertisement
Advertisement
Priority = 1
Priority = 25
Server

FIP Switch Discovery
Step 3: FIP-based FC Login
FCoE/FC
Switches
DCB Ethernet FC SAN
 FIP encapsulated FC Login
– Server sends FC Fabric Login (FLOGI) to selected switch
– Switch responds with FC FLOGI ACC (accept) with assigned FCID
 All further traffic is standard FC frames (FCoE encapsulated)
Priority = 25
FLOGI
FLOGI ACC
Server
Priority = 1

FCoE and Ethernet Standards
Fibre Channel over Ethernet
(FCoE)
– Developed by INCITS T11
Fibre Channel (FC) Interfaces
Technical Committee
– Enables FC traffic over Ethernet
– FC-BB-5 standard: June 2009
– FC-BB-6 expands solution
Data Center Bridging (DCB)
Ethernet
• Developed by IEEE
Data Center Bridging (DCB)
Task Group
• Drops frames as rarely as FC
• Commonly referred to as
Lossless Ethernet
• DCB: Required for FCoE
• DCB: Enhancement for iSCSI
Two complementary standards
Participants: Brocade, Cisco, EMC, Emulex, HP, IBM, Intel, QLogic, others

FC-BB-6 – New FCoE features
 Direct connection of servers to storage
– PT2PT [point to point]: Single cable
– VN2VN [VN_Port to VN_Port]: Single Ethernet LAN or VLAN
 Better support for FC fabric scaling (switch count)
– Distribute logical FC fabric switch functionality
– Enables every DCB Ethernet switch to participate in FCoE
More from Connectrix:
Storage Networking (FC/FCoE/iSCSI/VSN) Technology
& Best Practice Update
Mon 8:30am and Tue 3:00pm

Lossless Ethernet (DCB)
 IEEE 802.1 Data Center Bridging (DCB)
 Link level enhancements:
1. Enhanced Transmission Selection (ETS)
2. Priority Flow Control (PFC)
3. Data Center Bridging Exchange Protocol (DCBX)
 DCB: network portion that must be lossless
– Generally limited to data center distances per link
– Can use long-distance optics, but uncommon in practice
DCB Ethernet provides the Lossless Infrastructure
that enables FCoE. DCB also improves iSCSI.

Enhanced Transmission Selection
• Management framework for link bandwidth
• Priority configuration and bandwidth reservation
– HPC & storage traffic:
higher priority,
reserved bandwidth
• Low latency for
high priority traffic
– Unused bandwidth
available to other
traffic
DCB part 1: IEEE 802.1Qaz [ETS]
Offered Traffic
t1 t2 t3
Link Utilization (10Gig link)
3G/s HPC Traffic
3G/s
2G/s
3G/sStorage Traffic
3G/s
3G/s
LAN Traffic
4G/s
5G/s3G/s
t1 t2 t3
3G/s 3G/s
3G/s 3G/s 3G/s
2G/s
3G/s 4G/s 6G/s

Switch A Switch B
PAUSE and Priority Flow Control
• PAUSE can produce lossless Ethernet behavior
– Original 802.3x PAUSE affects all traffic: rarely implemented
• New PAUSE: Priority Flow Control (PFC)
– Pause per priority level
– No effect on other traffic
– Creates lossless virtual lanes
• Per priority flow control
– Enable/disable per priority
– Only for traffic that needs it
DCB part 2: IEEE 802.1Qbb & 802.3bd [PFC]

Data Center Bridging Capability eXchange
• Ethernet Link configuration (single link)
– Extends Link Layer Discovery Protocol (LLDP)
• Reliably enables lossless behavior (DCB)
– e.g., exchange Ethernet priority values for FCoE and FIP
• FCoE virtual links should not be instantiated without DCBX
DCB part 3: IEEE 802.1Qaz [DCBX]
FCoE/FC Switches
DCB Ethernet FC SAN
Server
DCBX

Ethernet Spanning Trees
 Reminder: FCoE is Ethernet only, no IP routing
– Ethernet (layer 2) is bridged, not routed
 Spanning Tree Protocol (STP): Prevents (deadly) loops
– Elects a Root Switch, disables redundant paths
 Causes problems in large layer 2 networks (for both FCoE and iSCSI)
– No network multipathing
– Inefficient link utilization
SiSiSiSi
SiSi SiSi SiSiSiSi SiSi
Root Switch

SiSiSiSi
SiSi SiSi SiSiSiSi SiSi
Ethernet Multipathing: SPBM and TRILL
 SPBM = Shortest Path Bridging-MAC [IEEE 802.1aq]
 TRILL = Transparent Interconnection of Lots of Links [IETF RFC 6325]
 Layer 2 routing for Ethernet switches
– Encapsulate Ethernet traffic, use IS-IS routing protocol
– Block Spanning Tree Protocol
 Transparent to NICs
All links active 

Ethernet Cabling Choices
Type / Connector Cable 1Gb 10Gb 40/100Gb
Copper
(10GBase-T) /
RJ-45
Cat6 or Cat6a Most existing
cabling (lots
of Cat 5e)
Some products on
market, but not for
FCoE yet. For 10Gb
Ethernet:
Cat6 55m
Cat6a 100m
Not supported
(insufficient
bandwidth)
Optical
(multimode) /
LC
OM2
(orange)
OM3 (aqua)
OM4 (aqua)
Rare for
Ethernet
Standard for
FC
Most backbone
deployments are
optical.
OM2 82m
OM3 300m
OM4 380m
Primarily
optical (QSFP+
connector)
OM3 100m
OM4 125m
Copper /
SFP+DA (direct
attach)
Twinax N/A Low power
5-10m distance
(Rack solution)
Different short-
distance option
(QSFP+)
Think of as
part of
connected
equipment

Agenda
• Conclusion

Live Virtual Machine Migration
C:
Shared storage:
Move VM without
moving stored data
Storage networking:
Enabler of shared
storage

virtual switch Hypervisor driver
Storage Drivers and Server Virtualization
NIC NICFC
HBA
FC
HBA
vNIC vNICvSCSI vSCSI
Hypervisor
*iSCSI initiator can also be in the VM
iSCSI traffic FC trafficLAN traffic

virtual switch Hypervisor driver
Storage Drivers and Server Virtualization
NIC NIC
vNICvSCSI vSCSI
Hypervisor
iSCSI traffic
vNIC
*iSCSI initiator can also be in the VM
FC
HBA
FC
HBA
C
N
A
C
N
A
FCoE follows FC pathLAN traffic

Software FCoE and Server Virtualization
NIC NICFC
HBA
FC
HBA
Hypervisor
FCoE software in VMs would send traffic
through the virtual switch to the NICs
SW
FCoE
SW
FCoE
Hypervisor drivervirtual switch
Virtual Switches in
ESX/ESXi
(including Cisco
Nexus 1000v) and
Hyper-V are not
Lossless (no DCB)
Not a problem for
iSCSI, NFS or CIFS
in a VM

Software FCoE and Server Virtualization
NIC NICFC
HBA
FC
HBA
Hypervisor
FCoE software in VMs would send traffic
through the virtual switch to the NICs
SW
FCoE
SW
FCoE
Hypervisor drivervirtual switch
FCoE works in
Hypervisor or CNA
(just not in a VM) C
N
A
SW
FCoE

Agenda
• Conclusion

FCoE and iSCSI
FCoE
FC expertise / install base
FC management
Layer 2 Ethernet
Use FCIP for distance
Ethernet
Leverage
Ethernet/IP expertise
10 Gigabit Ethernet
Lossless Ethernet
iSCSI
No FC expertise needed
Supports distance
connectivity (L3 IP routing)
Strong virtualization affinity

iSCSI Deployment
• 10 Gb iSCSI solutions
– Traditional Ethernet (recover
from dropped packets using
TCP) or
– Lossless Ethernet (DCB)
environment (TCP still used)
• iSCSI: natively routable (IP)
– Can use VLAN(s) to isolate
traffic
• iSCSI: smaller scale solutions
– Larger SANs: usually FC
(e.g., for robustness,
management)
Ethernet
iSCSI SAN

Some iSCSI Best Practices
• Use a separate VLAN for iSCSI
– Direct visibility and control of iSCSI traffic
• Avoid mixing 1Gb/sec and 10Gb/sec Ethernet
– Congestion can occur where speed changes
• DCB (lossless) Ethernet helps iSCSI, but not a panacea
– E.g., Still shouldn’t mix 1Gb/sec and 10Gb/sec Ethernet
Top Tips From E-Lab

Convergence: Server Phase
 Converged Switch at top of rack or end of row
– Tightly controlled solution
– Server 10 GE adapters: CNA or NIC
 iSCSI and FCoE via Converged Switch
FC HBAsNICs
Converged
Switch
Rack Mount
Servers
10 GbE CNAs
FC Attach
Ethernet LAN
Storage
Fibre Channel SAN
Ethernet
FC
iSCSI

Convergence: Network Phase
 Converged Switches move out of rack
 FCoE: Multi-hop, may be end-to-end
 Maintains existing SAN/network management
Overlapping admin domains may compel cultural adjustments
Converged
Switch
10 GbE CNAs
Ethernet LAN
Storage
Fibre Channel SAN
Ethernet
FC/FCoE
Ethernet Network
(IP, FCoE) and CNS
Rack Mount
Servers

Convergence at 10 Gigabit Ethernet
 Two paths to a Converged Network
– iSCSI: purely Ethernet
– FCoE: mix FC and Ethernet (or all Ethernet)
▪ FC compatibility now and in the future
 Choose (one or both) on scalability,
management, and skill set
10 GbE CNAs
Ethernet LAN
FC & FCoE
SAN
iSCSI/FCoE
Storage
Ethernet
FC/FCoE
Fibre Channel
& FCoE attach
Rack Mount
Servers
Converged
Switch

EMC and Ethernet
 TechBooks (Google: “FCoE Tech Book”)
– Fibre Channel over Ethernet (FCoE) Data Center Bridging
(DCB) Concepts and Protocols
– Fibre Channel over Ethernet (FCoE) Data Center Bridging
(DCB) Case Studies
▪ Includes blade server case studies
 Services
– Design, Implementation, Performance and Security offerings
for networks
 Products
– Ethernet equipment for creating Converged Network
Environments

Agenda
• Conclusion

Conclusion
 Converged data centers can be built using 10Gb Ethernet
– FCoE: Compatible with continued use of FC under common
management
– iSCSI solutions work well for all IP/Ethernet networks
 10 Gigabit Ethernet solutions are maturing
– Standards enable integration into existing data centers
– FCoE and iSCSI will follow Ethernet roadmap to 40 and 100
Gigabits/sec
 FC will follow FC roadmap to 16GFC and 32GFC speeds
 Achieving a converged network: Consider technology,
processes/best practices and organizational dynamics

Agenda
• Conclusion
• Bonus: iSCSI and RDMA

DMA = Direct Memory Access
 Improvement on Programmed I/O
 Used by FC HBAs and FCoE CNAs
Server
CPU
I/O
RAM
Programmed I/O
via CPU
Server
CPU
I/O
RAM
Direct Memory
Access (DMA) I/O

Remote Direct Memory Access (RDMA)
 Connect DMA over network or other interconnect
– Requires RDMA I/O hardware
Server
CPU
I/O
RAM
Server
CPU
I/O
RAM
Remote Direct Memory
Access (RDMA)

Access (RDMA)
RDMA and Storage
 Storage Systems often have CPU/RAM/etc.
 RDMA can optimize message and data transfer
Server
CPU
I/O
RAM
CPU
I/O
RAM
Storage
System

Access (RDMA)
RDMA and iSCSI
 Storage Systems often have CPU/RAM/etc.
 RDMA can optimize iSCSI message and data transfer
Server
CPU
I/O
RAM
CPU
I/O
RAM
Storage
System
Link
IP
TCP
iSCSI
SCSI

Access (RDMA)
RDMA and iSCSI: iSER
 iSER: iSCSI Extensions for RDMA
 iSER optimizes (and extends) iSCSI for RDMA
Server
CPU
I/O
RAM
CPU
I/O
RAM
Storage
System
RDMA
iSER
iSCSI
SCSI

iSER (iSCSI Extensions for RDMA)
 Based on and extends iSCSI
– Standardized in 2007 (IETF RFC 5046)
– NEW standard (match implementations): RFC 7145 (2014)
 Supports multiple RDMA transports
– InfiniBand (iSER: preferred block storage protocol)
– RoCE: RDMA over Converged [DCB] Ethernet
▪ RoCEv2 to add IP routing (aka Routable RoCE):
Under development by IBTA (InfiniBand Trade Association)
– iWARP: RDMA over TCP/IP
 Watch this space ...

Related Session and Resources
 Breakout – Storage Networking (FC/FCoE/iSCSI/VSN) Technology &
Best Practice Update
– Monday, 8:30am and Tuesday, 3:00pm
 Birds of a Feather – Storage Networking: Network Virtualization &
Multi-Tenant Storage
– Wednesday, 1:00pm
 EMC Support Matrix
– http://elabnavigator.emc.com
 EMC FCoE Introduction whitepaper
– http://www.emc.com/collateral/hardware/white-papers/h5916-intro-to-fcoe-wp.pdf
 Storage Networking Blog by Erik Smith (Connectrix)
– http://www.brasstacksblog.typepad.com

Q&A

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