Module 7: IP SAN, FCoE, NVMe-OF (iSCSI Overview) Flashcards
How does iSCSI work?
SCSI commands/data placed as payload into IP packets - TCP/IP protocol provides reliability and flow control
How does the SCSI protocol change in iSCSI?
remains unchanged even when transported over Fiber or FC
How does iSCSI identify devices to send data to and from?
SCSI IO protocol uses Initiator and Target labels
What is a source device in iSCSI?
typically a compute node - request connection to storage device that contains data to read/write
What is a target device in iSCSI?
storage devices that responds/establishes connection to source
What are the key components of an iSCSI communication?
iSCSI Initiator (EX: iSCSI HBA)
iSCSI Target (EX: SAN)
IP-Based Network (Gigabit Ethernet LAN)
How do software iSCSI initiators work?
performed by server OS - consumes CPU that takes performance from apps
What is the benefit of a hardware iSCSI initiator?
removes the processing demand from the server CPU
What is a hardware iSCSI initiator?
dedicated host based NIC to handle iSCSI processing functions
What are the types of iSCSI initiator setups?
Standard NIC w/ software iSCSI adapter
TOE NIC w/ software iSCSI adapter
iSCSI HBA
What are the advantages of software iSCSI initiators?
allow standard embedded or Ethernet NICs to be used
least expensive and easy to implement
What is a TOE NIC?
offloads TCP/IP processing from server CPU - leaves only iSCSI functionality to be processed
How does TOE NIC w/ software iSCSI adapter work?
compute passes the iSCSI info to the TOE NIC and then the TOE NIC sends info to target over TCP/IP
What makes TOE NIC w/ software iSCSI adapter better than Standard NIC w/ software iSCSI adapter?
improves performance by offloading some workloads - iSCSI still handled by CPU though so still pulls performance
What is an iSCSI HBA?
a hardware adapter w/ built in iSCSI functionality - offloads entire iSCSI and TCP/IP processing from CPU - most expensive way
What is a Native iSCSI setup?
iSCSI initiators attached to iSCSI targets directly through IP network - no FC components
What is a Bridged iSCSI setup?
iSCSI initiators are attached to IP network - storage systems attached to FC SAN - iSCSI gateway provides bridging functionality
What is an iSCSI Address?
logical path to an iSCSI initiator or target
What does an iSCSI Address consist of?
Location of iSCSI initiator or target (IP Address + TCP Port Number)
iSCSI Name (unique identifier for iSCSI network)
What are the three types of iSCSI Names?
iSCSI Qualifed Name (IQN)
Extended Unique Identifer (EUI)
Network Address Authority (NAA)
What is a VLAN?
one or more logical Ethernet LANs that operate over single physical Ethernet LAN
What are VLANs used for?
to isolate communication between a group of nodes indpendent of physical location across the network
What is the physical LAN for in a VLAN?
used to provide hardware level connectivity and maintain transport paths
Why are VLANs well suited for iSCSI networks?
enable full iSCSI traffic isolation from from other non-SAN traffic - provides high security
What is VLAN tagging?
performed by inserting 4 byte tag field containing 12-bit VLAN ID into the ethernet frame before its transmitted through an interswitch trunk
How many VLANs can a VLAN TAG address up to?
4096 VLANS
How does VLAN tagging work?
switch reads VLAN tag and forwards Ethernet frame to port assigned to VLAN ID
What does TOE stand for in TOE NIC?
TCP Offload Engine
What do you need to have a Bridged iSCSI environment?
MP (multiprotocol) Switch - also called iSCSI gateway
