Transcript R_MOD_05-Host_Integration_Basics

Host Integration Basics
Upon completion of this module, you should be able to:
• Identify storage network topologies and requirements
• Describe PowerPath features and functions
• Describe Unisphere Agent and Unisphere Server Utility
considerations
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Host Integration Basics
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Host Integration Basics
Lesson 1: Storage Network Topologies and Requirements
This lesson covers the following topics:
• Identifying Network Technologies
• Identifying Fibre Channel components, addressing, and
Connectivity rules
• Identifying iSCSI components, addressing, and Connectivity
rules
• Explaining host connectivity requirements
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Network Technologies
Network technologies offer more flexibility and distance
capabilities than typical channel technologies
Some characteristics of network technologies are:
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Low performance
High protocol overhead
Dynamic configuration
Long distance
Connectivity among
different systems
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Storage Area Network Management
• SANs are networks of host and storage devices often connected
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over Fibre Channel Fabrics
A common method of managing the variety of devices on a SAN
is SNMP
 Out of Band
• The FibreAlliance is defining the SNMP MIB to facilitate SAN
management
 The Fibre Channel Management Integration (FCMGMT-INT) MIB
provides a heterogeneous method of managing multiple devices
across a SAN
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Fibre Channel
• Fibre Channel is a serial data transfer interface
 Copper Wire Connection
 Optical Fiber Connection
• High-speed is obtained through:
 Mapping networking and I/O protocols to Fibre Channel constructs
 Encapsulating them and transporting them within Fibre Channel frames
Host Bus Adapters
Windows
Host
Linux
Host
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Storage
Fibre Channel
Switch
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Host Bus Adapter (HBA)
A Host Bus Adapter is an I/O
adapter that sits between the
host computer's bus and the
Fibre Channel loop
• Manages the transfer of information
Performs many low-level
interface functions
automatically
• Minimizes the impact on host processor performance
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Multiple Technologies
The HBA enables a range of
high-availability and storage
management capabilities
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Fibre Channel
iSCSI
FICON
SCSI
Load balance
Fail-over
SAN administration
Storage management
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Fibre Channel Addressing
• Fibre Channel Addresses are required to route the frames from
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source to target
24 bits (3 bytes) physical addresses are assigned when a Fibre
Channel node is connected to the switch (or loop in the case of
FC-AL)
Target
FC Switch
Source
FC Initiator:
HBA
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FC Responder:
SP Ports
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Viewing SP Fibre Channel Port Properties
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Switched Fabric Topology
• Switched Fabric is a Fibre Channel topology where many devices
connect with each other via Fibre Channel switches
 This topology allows for the most number of connections with a
theoretical 16 million devices per Fabric
• Frames are routed between source and destination by the Fabric
Fibre Channel
Switch
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Single Initiator Zoning
• Always put ONLY one HBA in a
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zone with Storage ports
Each HBA port can only talk to
Storage ports in the same
zone
HBAs & Storage Ports may be
members of more than one
zone
HBA ports are isolated from
each other to avoid potential
problems associated with the
SCSI discovery process
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Single Emulex HBA zoned to two VNX ports
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iSCSI Overview
iSCSI
• An IP-based protocol for establishing
and managing connections between
IP-based storage devices, hosts, and
clients
• A method to transfer block data using
a TCP/IP network
• Works by wrapping SCSI commands
into TCP Packets to transport them
over an IP network.
• Route or switch on standard Ethernet
equipment.
• Can use existing TCP/IP infrastructure
• Bridging devices can be used between
IP network and SAN
• No Fibre Channel content needed
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IP Network
IP Network
iSCSI/FC
Gateway
FC
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iSCSI Device Options
Network Interface Card (NIC)
• Checksum offload
• Fragmentation, out of order packets handled
by host
• Could hurt system performance
NIC with TCP Off-load Engine (TOE)
• Full TCP/IP offload
• Fragmentation, out of order packets handled
by TOE
• Increased memory/processing requirements
• iSCSI & SCSI handled by host
iSCSI Host Bus Adapter (HBA)
• Full TCP/IP+iSCSI/SCSI
• Completes storage connection
• Runs all layers on HBA
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iSCSI Names
• An iSCSI address
 Uniquely identifies nodes
 There are Two variations
 iqn. – iSCSI Qualified Name
 iqn.1992-04.com.emc:cx.fcntr073900083.a4
 eui. – Extended Unique Identifier
 eui.5006016141e0163a
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iSCSI Front-end Port Properties
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iSCSI CHAP Security
• Challenge Handshake Authentication Protocol
CHAP Target sends challenge to CHAP initiator
2. Initiator responds with a calculated value to the target
3. Target checks the calculated value, and if it matches, login
continues
4. If mutual CHAP is enabled, initiator will authenticate target using
the same process
1.
• One-way and Mutual CHAP
 Target and Initiator configured the same
• Configuration
 Unisphere – Array
 Host NBAs – Vendor Specific Tools
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iSCSI Network Requirements
• LAN configuration allows Layer 2 (switched) and Layer 3 (routed)
networks
 Layer 2 networks are recommended over Layer 3 networks
• The network should be dedicated solely to the iSCSI
configuration
 For performance reasons EMC recommends that no traffic apart
from iSCSI traffic should be carried over it
 If using MDS switches, EMC recommends creating a dedicated
VSAN for all iSCSI traffic.
 The network must be a well-engineered network with no packet
loss or packet duplication.
 vLAN tagging protocol is supported
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iSCSI Basic Connectivity Verification
• Ping
 Check basic connectivity
• Trace Route
 Provides information on number of hops required for the packet to reach
its destination
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iSCSI and FC Host Connectivity Rules
• All connections from a host to an array must use the same
protocol
 Connections must be all FC or all iSCSI
 NIC and HBA iSCSI connections cannot be mixed in the same server
 A server must have all NIC iSCSI connections or all HBA iSCSI
connections
 Do not connect a single server to both an FC storage system and
an iSCSI storage system
• Servers with iSCSI HBAs and servers with NICs can connect to the
same iSCSI storage system
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Host Integration Basics
Lesson 1: Summary
During this lesson the following topics were covered:
• Identifying Network Technologies
• Identifying Fibre Channel and iSCSI components and
addressing
• Explaining FC and iSCSI connectivity rules
• Explaining host connectivity requirements
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Host Integration Basics
Lesson 2: PowerPath and Other Host Utilities
This lesson covers the following topics:
• Describe PowerPath Features and Functions
• Describe Unisphere Agent and Unisphere Server Utility
Considerations
• Implement Host Utilities
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PowerPath
Host-Based Software
• Provides Path Management
Multiple Storage System Support
Multiple OS Support
Supports Fibre Channel and iSCSI
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Features and Functionality
Automatic path failover and path restore
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HBA/NIC
Interconnect
Switch
Interface
Interface Port
Dynamic multipath load-balancing
• Host by Host basis
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Array and OS Support
Supports all EMC-branded storage arrays
• All currently-shipping and supported models of VNX
• Both Fibre Channel and iSCSI interconnects
Supports several third-party, non-EMC storage arrays
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IBM ESS (Shark)
Hitachi Lightning
HP-branded Hitachi (HPXP)
HP StorageWorks EVA
EMA
HSG80
Supports major host operating systems
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Solaris
Windows Server
HP-UX
Linux Enterprise (Red Hat and SUSE)
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Integration with Volume Managers
Logical Volumes reside above native devices and
PowerPath devices in the I/O stack
PowerPath has been qualified for compatibility
with most major third-party volume managers
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Solstice Disk Suite, Veritas, VCS on Solaris
Veritas, native LVM on HP-UX
Veritas, native LVM on AIX
Sistina LVM on Linux
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Device States
A native device path can be in one of two States:
• Live: the path is usable for I/O activity
• Dead: the path has been detected as Failed by
PowerPath
All paths are tested periodically for a possible
change of state
• Dead paths are restored automatically by PowerPath
after they are repaired
• Only paths currently marked Live by PowerPath can
service I/O requests, and participate in load-balancing
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Device Modes
Mode can be set per LUN
• Reserves Bandwidth
Active mode
• Path is available to PowerPath for servicing I/O
• Default Mode, can be manually changed by the
administrator
Standby Mode
• Path is available to PowerPath, but is not servicing I/O
• Used in failure scenarios
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Active/Passive Arrays: Failover Mechanism
Host
• Two types of path failover:
 Array-initiated LUN trespass
 Typical cause: an SP fails or needs
to reboot
 PowerPath logs a follow-over
 Host-initiated LUN trespass
 PowerPath detects a path failure,
e.g. due to a cable break, port
failure etc.
 PowerPath initiates a trespass,
and logs the event
Active
Passive
Fabric A
Fabric B
Trespass
SP-A
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SP-B
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Active/Active Mode (ALUA)
• Asymmetric Logical Unit Access (ALUA)
Front-End Fault Masking
 Asymmetric accessibility to logical
units through various ports
 Request forwarding
implementation
 Communication method to pass
IO’s between SP’s
 Software on the controller
forwards requests to the other
controller
Back-End Fault Masking
• Not an Active-Active Array model!
 I/Os are not serviced by both SPs for a
given LUN
 I/Os are redirected to the SP owning
the LUN
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Symmetrical Active-Active: Overview
CX: Active-Passive
VNX: Active-Active
(ALUA)
Active-Active
(Symmetrical)
LUN
LUN
LUN
• Only one SP serves IOs via a given LUN
• The remaining SP is acting as standby
• SP trespasses LUN when paths fail and
host software adjusts to new path
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LUN
• LUN is presented across both SPpaths via internal links
• Only one SP is actively processing IO
to the backend
• Host initiates trespass when path fails
• Both SPs serve IOs to and from a given
LUN
• If path fails, no disruption to LUN
• The performance is now improved up
to 2X
• Classic LUNs only!
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Asymmetric LUN Access: VNX
SP reports SCSI descriptor:
I/O resumes to LUN
through alternate SP
after short delay
 TARGET_PORT_GROUPS
 Active/Optimized
 Active/Non-Optimized
ALUA masks
the failure and
trespasses
LUN
SPA
SPA
SPB
Owned
by SPA
Optimized Path
SPB
Owned
by SPB
Non-optimized Path
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Symmetric LUN Access: VNX with MCx
• Both SPs send and receive
I/O continues through
remaining SP and
paths with NO delay
 Active/Optimized
• Classic LUNs ONLY (OE R5.33)
SPA
SPA
SPB
Owned
by SPA
Optimized Path
Non-optimized Path
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SPB
Owned
by SPA
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LUN Parallel Access Locking Service
• Required for Active-Active access
SPA
CMI
Lock
SPB
Lock
LUN
• Write I/O operation acquires a lock on LBA address on both SPs
• Lock requests sent over CMI
• Lock requests are smaller/quicker than the entire I/O
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VNX with Symmetric / Active-Active Benefits
• Lower risk with increased availability within data centers
• Improved Availability
 All Paths are Active
 No trespass during path failure
 No trespass during NDU
• No setup on VNX or Host side
• Improved Performance
 All Paths serving I/O
LUN
 Up to 2X Improvement
• Eliminate application timeouts
• Improve application throughput
• Multi-path load balancing
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Requirements for Unisphere Host Agent, Unisphere
Server Utility
Supported version of the operating system
EMC VNX supported HBA hardware and driver
installed
Each SP must have an IP connection
Have a configured TCP/IP network connection to
any remote hosts
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Installing Unisphere Host Agent or Server Utility
Host agent and server utility can be installed on the same
attached server
If both are installed:
• Registration feature of the server utility will be disabled
• The host agent will be used to register the server’s NICs or HBAs to the storage
system
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Unisphere Server Utility: Install Rules for NIC
Initiators
• Must use Unisphere Server
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Utility
Microsoft iSCSI initiator, you
must install the Microsoft
iSCSI Software
Do not install the server
utility on a VMware Virtual
Machine.
Do not disable the
Registration Service option
Reboot the server when the
installation
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Host Integration Basics
Lesson 2: Summary
During this lesson the following topics were covered:
• Describe PowerPath Features and Functions
• Describe Unisphere Agent and Unisphere Server Utility
Considerations
• Implement Host Utilities
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Summary
Key points covered in this module:
• Each network technology has key components, addressing, and
connectivity requirements that must be followed to enable host
connectivity.
• PowerPath provides path management essential for
multipathing and high availability.
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