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diff --git a/unit3/unit3.typ b/unit3/unit3.typ index ad9b29c..fa5d2de 100644 --- a/unit3/unit3.typ +++ b/unit3/unit3.typ @@ -2,6 +2,7 @@ *Unit 3: Physical Layer* ] #set text(12pt) +#set heading(numbering: "1.1") #set page( header: [ #box()[ @@ -204,7 +205,6 @@ _Parity is a RAID technique to protect striped data from drive failure by perfor - Storage system has OSD storage component. - This component manages access to the object on the storage system. - OSD storage component converts object-level request to block-level request. -// #pagebreak() == Storage System Architecture - Critical design consideration for building cloud infrastructure. - Provider must choose additional storage and ensure capacity to maintain overall performance of the environment. @@ -317,3 +317,211 @@ _Parity is a RAID technique to protect striped data from drive failure by perfor - These disks are configured by the OSD node to store object data. 4. *Storage*\ = Network +- Establishes communication pathways between devices. +- Devices in networks called nodes. +- Enables information exchange and resource sharing among large number of nodes over long distances. +- Networks can connect to other networks to enable data transfer between nodes. +- Providers leverage different types of networks, with different protocols supporting different classes of network traffic. +- Cloud requires reliable and secure network connectivity to access cloud services. +- Provider connects cloud to a network enabling clients to connect to cloud over over network and use cloud services. +- Providers may also use IT resources at one or more data centers to provide cloud services. +- If multiple data centers are deployed, IT resources are logically aggregated by connecting them in a WAN. +== Types of network communications +=== Compute-to-Compute Communication. +#figure( + image("./assets/compute to compute.png") +) +- Interconnecting physical compute systems enables compute-to-compute communication. +- Typically uses IP-based protocols. +- Each physical compute is connected to the network over a physical NIC. +- Physical switches and routers are commonly used. +- Providers have to ensure appropriate switches and routers, with appropriate bandwidth and ports are provided. +=== Compute-to-Storage Communication +_A Storage Area Network (SAN) is a network that interconnects storage systems with compute systems, enabling compute systems to access and share the storage systems._ +- Sharing improves the utilization of the storage systems. +- Using a SAN facilitates centralized storage management. +- This simplifies and standardizes management efforts. +==== Types of SAN +===== Fibre Channel SAN (FC SAN) +_FC SAN is a high speed, dedicated network of compute systems and shared storage systems that uses Fibre Channel protocols to transport data, commands, and status information between compute and storage systems._ +- FC protocol implements the Small Computer System Interface (SCSI) command set. +- It also supports: + 1. Asynchronous Transfer Mode (ATM) + 2. Fibre Connection (FICOM) + 3. IP +- SCSI over FC overcomes distance and accessability limitations associated with traditional SCSI. +- FC protocol provides block-level access to storage systems. +- It provides a serial data transfer interface. +- FC architecture is very scalable and a single FC SAN can accommodate approximatly 15 million nodes. +====== FC SAN Components +#table( + columns: (auto, auto), + table.header([ Component ], [ Description ]), + [ Network Adapters ],[ + - Provide physical interface to a node for communicating with other nodes. + - Examples: FC HBAs and storage system front-end adapters. + ], [ Cables and connectors ], [ + - Optical fiber cables are predominantly used to provide connectivity. + - Connectors enable cables to be swiftly connected to and disconnected from ports. + ], [ Interconnecting devices ], [ + - FC switches and directors. + - Directors have a modular design, higher port count, and better fault tolerance. + - Switches have either a fixed port count or modular design. + ] +) +====== Fabric Connect and Addressing +- A fabric is created with an FC switch/director/network of switches that enable all nodes to connect and communicate. +- Each switch has unique domain identifier (ID). +- Each network adapter and port has a globally unique 64 bit identifier called WWN (World Wide Name). +- WWN is a static name. +- WWNs are burned into hardware or assigned through software. +- An FC network adapter is physically identified by a World Wide Node Name (WWNN). +- Each port on the adapter has a unique World Wide Port Name (WWPN). +- Each FC adapter port in fabric has a unique 24 bit FC address for communication. +====== Fabric Port Types +#figure( + image("./assets/fabricporttypes.png") +) +A port in a switched fabric can be one of the following types: +1. *N_Port* is an end-point in fabric. This is also known as the node port. Typically, it is a compute system port or a storage system port connected to a switch in fabric. +2. *E_Port* is a switch port that forms a connection between two FC switches. This port is also known as an expansion port. The E_Port of an FC switch connects to the E_Port of another FC switch in the fabric through ISLs. +3. *F_Port* is a port on a switch that connects an N_Port. It is also known as a fabric port. +4. *G_Port* is a generic port on some vendors' switches. It can operate as an E_Port of F_Port and determines it;s functionality. +====== Zoning +_An FC switch function that enables node ports within a fabric to be logically segmented into groups and to communicate with each other within the group._ +- When fabric is changed, it sends a Registered State Change Notification to the nodes in the fabric. +- Without zoning, RSCNs are revieved by all nodes even those not impacted by the change. +- This results in increased traffic. +- For large fabrics, this increase in traffic can be significant and impact compute-to-storage data traffic. +- Zoning limits the number of RSCNs in fabric. +- Zoning allows for fabric to send RSCNs only to affected nodes. +- Both node and switch ports can be part of a zone. +- A port or node can be part of multiple zones. +- HBA ports called initiator ports and storage ports called target ports. +- Single-initiator-single-target zoning is considered industry standard. +- Single-initiator-single-target zoning eliminates unnecessary compute-compute interactions and minimizes RSCNs. +====== Types of Zoning +#figure( + image("./assets/typesofzoning.png") +) +#table( + columns: (auto, auto), + table.header([ Type of zoning ], [ Description ]), + [ WWN Zoning],[ + - Uses WWNs to define zones. + - Zone members are WWPN addresses of ports in HBA and it's targets. + - A major advantage of WWN zoning is it's flexibility. + - It allows nodes to be moved to another switch port in the fabric and maintain connectivity to their zone partners without modifying zone configuration. + - This is possible because WWN is static to the node port. + ], [ Port Zoning ], [ + - Uses switch port identifier to define zones. + - Access to data is determined by the physical switch port to which the node is connected. + - Zone members are the port identifier to which HBA and targets are connected. + - If node is moved to another switch port, zone configuration must be altered. + - If an HBA fails, it can be replaced without changing zoning configuration. + ], [ Mixed Zoning ], [ + - Combines qualities of WWN zoning and Port zoning. + - Enables specific node ports to be tied to the WWN of a node. + ] +) +===== Internet Protocol SAN (IP SAN) +_A SAN that uses Internet Portocol (IP) for the transport of storage traffic. It transports block I/O over an IP-based network._ +- Providers may have existing IP-based network infrastructure which could be used for storage networking. +- More economical as it leverages existing IP-based network instead of creating a new FC SAN network. +- Robust and mature security options available for IP networks. +- Many long-range disaster recovery solutions leverage IP-based networks. +- Two Main Protocols are iSCSI and FCIP. +====== iSCSI +#figure( + image("./assets/iSCSi.png") +) +_iSCSI encapsulates SCSI commands and data into IP packets that are transported over an IP-based network._ +- The network components include: + 1. *iSCSI initiators* such as software iSCSI adapter and iSCSI HBA. + 2. *iSCSI targets* such as a storage system with iSCSI port or an iSCSI gateway. + 3. *IP-based network*. +- This sends commands and associated data to a target and the target returns data and responses to the initiator. +- The software iSCSI adapter is an OS kernal-resident software that uses an existing NIC of the compute system to emulate an iSCSI initiator. +- An iSCSI HBA has a built-in iSCSI initiator and is capable of providing performance benefits over software iSCSI adapters. +- This is done by offloading the entire iSCSI and TCP/IP from the processor of the comput system. +- If an iSCSI capable storage system is deployed then iSCSI initiator con directly communicate with the storage system over IP-based network. +- If storage is not compatible then iSCSI gateways are used. +- The gateway transforms the IP packets into FC frames and vice versa. +- If gateway is present then it is bridged iSCSI else it is native iSCSI. +====== iSCSI Name +_A worldwide unique iSCSI identifier that identifies the initiators and the targets within an iSCSI network to facilitate communication._ +- Can be a combination of: + 1. Department name + 2. Application + 3. Manufacturer + 4. Serial number + 5. Asset number + 6. Tag used to recognise and manage devices. +- Allowed special characters are dots, dashes and blank spaces. +- Two types of iSCSI names are: + 1. *iSCSI Quantified Name (IQN)* + - An organization must own a registered domain name to generate IQN. + - Domain need not be active or resolve to an address. + - Needs to be reserved to prevent domain reuse. + - Date is included with the name to prevent collisions. + - Any identifiers like serial number, asset number are added to the end. + - Example: _iqn.2025-12.com.example:optional_string_ + 2. *Extended Unique Identifier (EUI)* + - Globally unique identifier based on IEEE EUI-64 standard. + - Composed of "eui" prefix and 16-character hexadecimal name. + - Example: _eui.123456789ABCDEF_ +====== FCIP +#figure( + image("./assets/fcip.png") +) +_FCIP is an encapsulation of FC frames into IP packets that are transported between FC SANs over an IP-based network through FCIP tunnel._ +- Enables data transfer between disparate FC SANs. +- FCIP entity deployed at either ends of a tunnel between two FC SAN islands. +- The gateway encapsulates FC frames into IP packets and transfers them through the tunnel. +- The remote gateway decapsulates the FC frames from the IP packets and sends them to the FC SAN. +- Used extensivly for disaster recovery in which data is replicated at a remote site. +- Capable of merging interconnected fabrics into a single fabric. +- In a merged fabric, the traffic travels between interconnected FC SANs through FCIP tunnel. +- Only a small subset of nodes need to be connected via FCIP. +- Majority of FCIP implementations use some switch-specific feature to prevent the fabrics from merging. +- They also restrict nodes allowed to communicate across fabrics. +===== Fibre Channel over Ethernet SAN (FCoE SAN) +_FCoE SAN is a converged enhanced ethernet (CEE) network that uses the FCoE protocol to transport FC data along with regular ethernet traffic over high speed ethernet links. FCoE encapsulates FC frames into ethernet frames._ +- Supports Data Center Bridging (DCB) functionalities. +- DCB ensures for lossless transmission of FC traffic over ethernet. +- Allows us to deploy the same network components for transferring compute-to-compute and FC storage traffic. +- Reduces the complexity of managing multiple discrete networks. +- Uses multi-functional network adapters and switches. +- Reduces the infrastructure, power, and space consumed in a data center. +#figure( + image("./assets/fcoesan.png") +) +#table( + columns: (auto, auto), + table.header([ Component ], [ Description ]), + [ Converged Network Adapter (CNA) ], [ + - Provides functionality of both NIC and FC HBA in a single device. + - Encapsulates FC traffic onto Ethernet frames. + - Consolidates both FC and regular Ethernet traffic over CEE links. + ], [ Software FCoE adapter ], [ + - A software on the compute system that performs FCoE processing. + - Supported NICs transfer both FCoE and regular Ethernet traffic. + ], [ FCoE Switch ], [ + - Contains Fibre Channel Forwarder (FCF), Ethernet Bridge, and a set of ports for FC, Ethernet, or FCoE connectivity. + - FCF encapsulates FC frames into Ethernet frames and vice versa. + ], [ FCoE storage port ], [ + - Connects to FCoE switch + - Enables end-to-end FCoE environment. + ] +) +=== Inter-Cloud communication +#figure( + image("./assets/icc.png") +) +- Cloud tenents of rapid elasticity, resource pooling, broad network create a sense of availability of limitless resources. +- Create a sense they can be accessed from anywhere over a network. +- However, single cloud does not have infinite resources. +- A cloud without adequate resources, may be able to satisfy requests if it is able to access resources from another cloud. +- Several combinations of inter-cloud communication. +- Allows clouds balance workloads by accessing and using computing resources from other cloud infrastructures. +- Providers must ensure network connectivity o cloud infrastructure over WAN to other clouds for resource access and workload distribution. |