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Storage Fundamentals Network Topologies and Connectivity Options. Ulla Vest – vest@de.ibm.com IBM TMCC Europe Executive Briefing Centers. Information Assets & Systems. Infrastructure Management. Retention & Lifecycle Management. Business Continuity. Resource Virtualization. Systems
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Storage Fundamentals Network Topologies and Connectivity Options Ulla Vest – vest@de.ibm.com IBM TMCC Europe Executive Briefing Centers
Information Assets & Systems Infrastructure Management Retention & Lifecycle Management Business Continuity Resource Virtualization Systems Storage Servers Networking Information Assets & SystemsThe Foundation for Information On Demand IBM Storage Networking Solutions
LAN (TCP/IP Protocol) LAN (TCP/IP Protocol) SAN (FC Protocol) LAN (TCP/IP Protocol) Server and Storage Connectivity Options Internal Storage DAS – Direct Attaced Storage iSCSI – SCSI over IP SAN – FC Storage Area Network NAS – Network Attached Storage
Dedicated Storage – Internal or Direct Attached • Distributed servers and storage - separate islands of information, separate storage management , storage/data ‘owned’ by one server Inefficient Use of Resources – more complex, higher Costs
Consolidated Storage • Ownership of storage resources is 'de-coupled' from servers • Consolidated storage systems, storage management, enterprise data • High agility and efficiency - reduced complexity, lower costs • Supports highly available, scalable, disaster tolerant enterprise solutions Consolidated Storage requires Network Approach
Reduced Cost through Networked Storage • $ per megabyte of user data 3-Year TCO • Based on 2TB of user data • Cost savings of SAN / NAS driven by: • Improved disk utilisation • Improved availability of enterprise information • Tape drive consolidation • Centralized management
SAN - Storage Area Network (Fibre Channel based) • Servers ‘see’ local disks (or tape drives) • SAN performs ‘Block I/O’: direct access to assumed disk sectors • SCSI commands, filesystem-unspecific Fibre Channel A dedicated Network Infrastructure for Data Traffic, designed for highest Performance, Availability, and Scale
What is Fibre Channel? • SCSI-3 based serial interface technology enabling SANs • High bandwidth - 100-400MB/s per link, 3200MB/s ISL Trunking • Up to 10km link distance supported (more with extenders) • Large, scalable configurations, hot plugging, reconfiguration • Set of open standards for • Media and physical interfaces - copper or fiber optical • Data transmission, link services and signaling protocol • Mapping of upper level protocols different command sets • SCSI/FCP, HIPPI, ESCON, FICON, and also IP, IPI, ATM Common Transport System for multiple Protocols
SCSI Bus vs Fibrechannel • Serial line solves bit-desynchronisation (skew) problem *80km with special material
Fibre Channel – Why not TCP/IP? • Internet protocol (IP) is packet-oriented: • Each packet finds its own route through the network • Additional transmission control layer (TCP/IP) required; CPU load • Jams at high traffic rates • Fibrechannel is channel-oriented: • Packets are joined to sequences using one single route • Less routing overhead • Transmission control built-in, no CPU load
Hub FC loop Switch Fibre Channel Topologies • Point-to-Point • Direct connection • Full duplex operation • Loop • Shared loop - up to 127 nodes • Shared bandwidth • Half duplex operation • Loop arbitration & loop initialization • Switched • Up to 16M nodes in a domain • Allows multiple concurrent connections • Full bandwidth between any two ports • Full duplex operation
Hub Hub Switch Switch Director Loop protocol Fabric protocol Mission Critical Topologies • Two HBAs in parallel plus multipathing software • Two Loops in parallel, two switches in parallel or high available, redundant core switches or directors
Restricting Access with Zoning • Zoning is a switch feature to increase security and restrict access - zones can overlap and are based on WWN or port • Proper isolation of devices that do not support LUN masking WWN = World Wide Name
FC SAN Benefits • Distance, performance & addressability • Data is more accessible & more available • More efficient use of storage resources • Improved management of TBs of data • Increased business flexibility • Optimized enterprise backup procedures • Information used to belong to the server – now it belongs to the Enterprise Provides the flexible Infrastructure required for an on demand Storage Environment
IBM SAN Suppliers Cisco MDS Multilayer Director / Fabric Switch Family (IBM Resale) IBM TotalStorage SAN b-type (Brocade OEM) IBM TotalStorage m-type (McDATA OEM) Portfolio Consolidation
Entry-level fabric switches IBM SAN16M-2 ÍBM SAN10Q-2 Cisco MDS 9020 IBM SAN16B-2 Mid-range fabric switches Enterprise-class directors IBM System Storage SAN Family IBM SAN32B-2 IBM SAN32M-2 Cisco MDS 9216i IBM SAN64B-2 IBM SAN256B IBM SAN140M / 256M Cisco MDS 9506 / 9509 / 9513
NAS - Network Attached Storage • Clients 'see' file system • NAS performs 'File I/O': file level acces • Multiple network file access protocols, filesystem specific An optimized IP Storage Device for File Sharing
Should I use SAN or NAS? • SAN • if attaching databases or running applications that require "their" disks • NAS causes more CPU overhead (TCP) here and saturates transmission lines earlier (Ethernet) • NAS • if sharing files or working with user access rights (=file server) • SAN disk content typically cannot be shared, except in clusters • SAN with NAS Gateway access • if sharing files and running databases in one environment
iSCSI – SCSI over IP • SCSI commands encapsulated in TCP/IP • Clients 'see' local disks (special software drivers required) • iSCSI performs 'Block I/O': direct access to assumed disk sectors Storage Area Network (SAN) over Ethernet
iSCSI Target Fields • "Outside the datacenter" • Server islands without Fibrechannel access • Use iSCSI router to make SAN storage available to non-FC servers • Where GB-Ethernet backbones exist • Consider a separate Ethernet "SAN" for high duty servers • For applications needing raw disk access • File-oriented applications are fine with NAS • Applications optimized for disk access should use iSCSI
iSCSI comes – Fibrechannel goes? • iSCSI uses economic LAN technology • No additional administrator skills (Fibrechannel) needed • Integrated iSCSI adapters (e.g. Adaptec) • IBM, Cisco, Microsoft, +... determination • Higher CPU & bandwidth overhead • But: No CPU overhead when using iSCSI adapters • Fibrechannel has still best network utilization at same clock rate • Fewer supported clients (yet) • Later technology, less gimmicks
NAS ‚Appliance‘ iSCSI ‚Appliance‘ NAS Gateway iSCSI Gateway SAN (FC Protocol) Storage Pool Storage Networking Options LAN (TCP/IP Protocol)