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iSCSI Protocol Analysis and Tools

iSCSI Protocol Analysis and Tools. Neeraj Reddy Kuppam neeraj@netapp.com. What are our goals today?. Learn iSCSI Protocol Setup and play with iSCSI SANs Learn basic iSCSI troubleshooting skills Have Fun while learning!!!!. Blocks protocols.

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iSCSI Protocol Analysis and Tools

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  1. iSCSI Protocol Analysis and Tools Neeraj Reddy Kuppam neeraj@netapp.com

  2. What are our goals today? • Learn iSCSI Protocol • Setup and play with iSCSI SANs • Learn basic iSCSI troubleshooting skills • Have Fun while learning!!!!

  3. Blocks protocols What is the relationship between SCSI, FC and iSCSI?

  4. SCSI-3 - “A path is a path” • SCSI-3 is a client-server I/O protocol • Targets – Data Provider/Server • 1 or more data containers called Logical Units (LUNs) • Initiators – Data Consumer/Client • Reads/writes data in units of blocks • SCSI-3 is transport-independent – Underlying transport mechanism and physical layer is not specified

  5. SCSI-3 is Transport independent Target Initiator LUN 0 LUN 1 TransportMechanism

  6. SCSI-3 CDBs & Responses Target Initiator SCSI_CMD LUN=3 CDB=28 00 00 10 … DATA_IN Length=4KB Data=01 02 … Transport Mechanism

  7. FCP-SCSI: Transport for SCSI-3 Target Initiator FC Frame: FCP-SCSI Subtype: SCSI_CMD LUN=3 CDB=28 00 00 … FC Frame: FCP-SCSI Subtype: DATA_IN Length=4KB Data=01 02 … FC Port FC Port FCFabric

  8. iSCSI – SCSI-3 over TCP/IP • iSCSI is a transport protocol for conducting SCSI-3 over standard TCP/IP networks • Defines message formats and rules • Operates as an Upper-Level Protocol within the TCP/IP networking framework • Peer to NFS, CIFS, HTTP, ... • Everything is a message – Protocol Data Unit (PDU)

  9. iSCSI: Transport for SCSI-3 Target Initiator IP hdr TCP hdr iSCSI PDU: SCSI_CMD LUN=3 CDB=28 00 00 … IP hdr TCP hdr iSCSI PDU: DATA_IN Len=4KB Data=01 02 … Ethernet Ethernet GbE 10 GbE 10/100 Mbps IPNetwork

  10. Why do we need the iSCSI Protocol? • Benefits of SANs... • Familiar block-level access • Dedicated appliance for storage management • Shared access to centrally managed storage • …without drawbacks of FC • No expensive dedicated FC infrastructure • Standard well-understood IP network routers, switches, cables, etc.

  11. Before we jump in to iSCSI concepts…. Let’s learn a little bit about iSCSI analyzers.

  12. iSCSI Protocol Analyzers • Hardware Analyzers • Finisar www.finisar.com • I-Tech www.i-tech.com • Agilent www.agilent.com • Software Analyzers • Ethereal www.ethereal.com • Network Associates SnifferPro www.mcafee.com • My Favorite • Ethereal www.ethereal.com • It’s Free !!

  13. iSCSI Protocol Analyzers – Ethereal • Ethereal • Open Source Network Analyzer • Under GPL • Windows and Unix executables available • Supports traces captured by other analyzers • To name a few: tcpdump (libpcap), NAI's Sniffer Pro, NetXray, Sun snoop and atmsnoop, Shomiti/Finisar Surveyor, AIX's iptrace, Microsoft's Network Monitor, Novell's LANalyzer, RADCOM's WAN/LAN Analyzer, HP-UX nettl, i4btrace from the ISDN4BSD project, Cisco Secure IDS iplog, the pppd log (pppdump-format), the AG Group's/WildPacket's EtherPeek/TokenPeek/AiroPeek.

  14. iSCSI Protocol by Example iSCSI Protocol concepts

  15. iSCSI Concepts: Sessions • iSCSI Session • communication path and state between initiator and target • iSCSI realization of a SCSI-3 I_T_NEXUS • consists of one or more TCP connections • PLUS state of in-progress commands Host Target Disk class driver I_T_Nexus SCSI Layer SCSI layer (Target) iSCSI Session iSCSI Initiator iSCSI Target CMD1 TCP connections CMD2

  16. iSCSI Concepts: Nodename, Aliases • iSCSI Nodename: • Worldwide-unique nodename, prescribed format • Examples: • iqn.1992-08.com.netapp:sn.35780522 • iqn.2001-01.com.vendor:hostname • eui.123456789abcdef0 • iSCSI Target Alias, Initiator Alias • For convenient identification • Free format • Examples: • oracle-host • qa-storage

  17. iSCSI Protocol Stack – the complete picture

  18. iSCSI Target Discovery Types of Discovery • Static Discovery • SendTargets Discovery • Dynamic Discovery • Let’s look at a SendTargets Discovery trace

  19. iSCSI Target Authentication CHAP • Challenge Handshake Authentication Protocol • All iSCSI targets and initiators MUST support CHAP. • Users are likely to make mistakes in CHAP configuration. • Let’s troubleshoot some authentication problems using traces.

  20. After Target Discovery • Normal Session • Scanning for LUs • Let’s look at a Bus Rescan Trace

  21. Resources • Use the iSCSI trace reading ability you picked up today to troubleshoot common problems. • NetApp iSCSI Products: http://www.netapp.com/products/storage-networking/ipsan/index.html

  22. I need your feedback…. • Tell me now…(or) • Send me an email.

  23. Storage Simplified

  24. + Shelf Shrunken Head modules What’s a FAS270c? + = Heads Shelves Storage Controller = FAS270c HA in a box + FCP!

  25. FAS270c Head 1 Head 2 FC (Fib) FC (Cu) Shelf Expansion Port 2XGbE Cu NICS Console port

  26. Enterprise Departmental Enterprise iSCSI DedicatedEthernet FibreChannel SAN(Block) NetApp Unified Storage Architecture SAN NAS Departmental CorporateLAN NAS(File) NetApp Fabric Attached Storage

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