In Linux systems, storage management is one of the most critical tasks for system administrators. The Logical Volume Manager (LVM) provides flexible storage management by abstracting physical disks into logical units. LVM’s Basic Structure LVM consists of three key layers: Physical Volume An actual disk or partition that has been initialized to be used by LVM. This can be a physical storage device like /dev/sda1, /dev/sdb. Volume Group A collection of physical volumes that are combined into a single storage pool. At this stage, the boundaries of the physical disks are removed, presenting one large storage space. ...

ARP(Address Resolution Protocol) is a protocol that finds the MAC address corresponding to an IP address. When communication occurs between devices on a network, it is necessary to find out the MAC address to deliver the packet to the destination. The Role of ARP Convert IP addresses to MAC addresses Identify devices that can communicate directly within the network Optimize performance through ARP caching Detect duplicate IP conflicts (using Gratuitous ARP) ARP Operation Process 1. ARP Request (ARP Request) When a host knows the destination IP address but not the MAC address, it broadcasts an ARP request to the network. ...

DNS (Domain Name System) is a system that translates domain names into IP addresses on the Internet. When a user tries to access a website by typing in its domain name, DNS translates it into the IP address of the corresponding server and facilitates the connection. Role of DNS Translate domain names to IP addresses Translate IP addresses to domain names (reverse lookup) Provide mail server information (MX records) Map multiple IPs for load balancing DNS Resolution Process DNS operates in a hierarchical structure and goes through the following steps: ...

The OSI (Open Systems Interconnection) 7-layer model is a conceptual framework that divides the process of network communication into seven distinct layers. Standardized by the ISO in 1984, it serves as the reference model for modern networks. Layer 7 - Application Layer The layer closest to the user, the Application Layer is where the user-facing applications we interact with operate. Key Protocols: HTTP: Web service communication FTP: File transfer SMTP: Email transfer DNS: Domain name resolution Practical Use Cases: ...

The concept of a subnet mask was introduced in the evolution of TCP/IP protocols around 1985. The early internet used a classful addressing system (A, B, C classes), which was proving to be too rigid, and inefficient for IP address allocation. Subnet masks came into the picture to address this issue. History and Need for Subnet Masks In the early days of the internet, the class of an IP address was determined by looking at just the first octet (byte) of the address: ...