localVsCloud+ BuTyoes + HyperVsESXi + WhatBU + Retention + RecoveryVsDisaster + Agent + Encryption + Virtualization + ServerVsVm +

What is On-Premises Backup?

On-Premises Backup is the Data which is stored locally at your office using hardware like servers or hard drives.

For example A company saves daily backups to a hard drive located inside the server room.

What is Local Backup?

A Local Backup is the Data which is stored on a physical device located nearby (like a USB Drive, hard drive, or local server), typically in the same area.

It’s Just like Saving important files to an external hard drive at your office desk.

Usage of Local Backup

Best for small to medium offices where fast daily or weekly backups are needed. It allows quick recovery and doesn’t require internet for restore

Cloud Backup - Definition

Cloud Backup is the Data which is stored on internet-based servers and managed by external providers in secure data centers.

Like Your phone automatically backing up photos to Google Photos.

Usage of Cloud Backup

Best for off-site protection, long-term storage, and remote access. Commonly used by both individuals and businesses.

Local vs Cloud Backup -

• Local and cloud backup mainly differ in location, safety, and restore speed.
  

• Local backup is stored on nearby devices such as external drives, while cloud backup is saved on internet-based servers.
  

• In terms of safety, local backup can be lost in events like fire or theft, but cloud backup is more secure from physical damage.
  

• For restore speed, local backup is usually faster since the data is on hand, while cloud backup can be slower as it depends on internet speed.

What is Recovery & When is it used?

It means getting back a lost or damaged file, folder, or system. Used Small-issues like Software crash, Accidental file deletion.

Example of Recovery

You delete a file by mistake and restore it from yesterday’s backup — that’s recovery.

What is Disaster Recovery & When is it used?

It means bringing back full IT systems after a big problem. Used in cases like fire, flood, power crashes or hacking.

Example of Disaster Recovery

Imagine your office servers are physically destroyed in a fire. Still You recover everything using cloud backup — that’s disaster recovery.

Recovery vs Disaster Recovery - Scope & Frequency & Goal

Recovery fixes small things by restoring particular files & folders and happens often. Disaster Recovery handles full system failures & rebuilds everything to keep the business running. and happens very rare.

What is Agent-Based Backup?

Backup Tools that uses small software or agent which are already installed inside the system to collect files and send backups to local, network or cloud storages.

How does Agent-Based Backup work?

Agent-based backup uses a lightweight software (called an agent) that runs inside the operating system and is responsible for identifying, compressing, encrypting, and sending the backup data to the backup server or storage.

Agent-Based Backup Like ?

Like placing a security guard inside each room who watches and reports everything to the control room.

What is Agentless Backup?

Backup Tools that doesn’t require any preinstalled software or agent inside the system. Instead they connect remotely to pull data for backup

How does Agentless Backup work?

It connects from outside and uses built-in tools like file-sharing, remote access, or backup settings to collect and save data.

Agentless Backup Like ?

Like flying a drone outside a building to watch through windows and record — without entering inside the building

When to use Agentless vs Agent-Based Backup?

Agentless is best for virtual/cloud servers where setup needs to be fast and lightweight.

Agent-Based is best for physical systems or where deep app-level control is needed.

What is Backup Encryption?

It means protecting your backup data by locking it with a password or secret key.

Even if someone tries to steal the backup, they can’t read it without the key.

It’s like putting your backup in a locked suitcase. Even if someone takes the suitcase, they can’t open it without the key.

Why is Backup Encryption important ?

Backup is Important due to 2 to 3 major reasons starting with

(Data Protection)
Even if your backup is stolen (like from a lost USB)
The data stays safe as a key is required to unlock the data.

(Protects sensitive info)

For businesses, backups may contain personal, medical, or financial data — because of which encryption is necessary to keep it confidential.

(Safe cloud storage)
Cloud backups without encryption are easy targets for hackers — encryption adds a strong protection layer.

Real-life example of Backup Encryption

Your company backs up customer data to Google Cloud.

Without encryption = hacker can read the files.

With encryption = the files are just random code which requires a secret key for unlocking it.

What is Virtualization?

Virtualization is a technology that allows you to run multiple virtual machines (VMs) on a single physical machine. Each VM acts like a real computer with its own OS, CPU, RAM, and storage, but all share the physical server's hardware.

Real-world Example of Virtualization

Imagine one big server in your office. Using virtualization, you divide it into multiple small computers (VMs): one for email, one for web hosting, one for databases, and one for backup. Each VM does a separate job on the same hardware.

Why Do We Use Virtualization? - Cost Saving

You don't need to buy separate physical machines for each service. Instead you save money by running multiple services on one server.

Why Do We Use Virtualization? - Better Resource Utilization

Instead of wasting resources on underutilized physical servers, virtualization allows multiple VMs to run on the same physical hardware, making far better use of CPU, RAM, and storage more efficiently.

Why Do We Use Virtualization? - Easier Management

You can create, delete, or move VMs easily without touching the physical hardware.

Why Do We Use Virtualization? - High Availability & Backup

VMs are easier to back up, clone, and restore quickly compared to physical systems.

Key Component: Hypervisor

The hypervisor is software that creates and manages VMs. on one physical computer.

It shares CPU, memory, storage between the physical machine and virtual machine.

Key Component: Virtual Machine (VM)

A virtual machine is a software-based computer that runs on the hypervisor and behaves like a real computer.

Type 1 Hypervisor (Bare Metal)

Installed directly on the physical server. Examples: VMware ESXi, Microsoft Hyper-V. Offers better performance and is used in data centers.

Type 2 Hypervisor (Hosted)

Installed like an application on top of a host OS (like Windows/Linux). Examples: Oracle VirtualBox, VMware Workstation. Used mostly for testing or learning.

What is a Physical Server?

A physical server is a real, tangible machine located in a data center or server room. It consists of dedicated hardware components such as CPU, RAM, storage, and other network interfaces.

What is a Virtual Machine (VM)?

A virtual machine is a software-based computer that runs inside a physical server using virtualization. It behaves like a real computer with its own OS, CPU, RAM, and storage.

Physical Server & Virtual Machine Illustrate through an Example

Think of the physical server as a building. Each VM is a separate apartment with its own furniture (OS and apps) but shares the same building and resources.

What is Backup Retention?

Backup Retention is the policy that defines how long backup data is stored before it is deleted or overwritten. Simple Example: It’s like deciding how long to keep photos in your phone—1 month, 1 year, or forever.

Why is Retention Important in Backup?

Retention is important because it ensures old backups are available when needed. It protects against data loss, meets basic legal requirements as per Industry Standard, manages storage space, and allows recovery from ransomware attacks.

How does Backup Retention help with Data Loss Protection?

Retention keeps old backups so if something is accidentally deleted or if a system fails, you can restore the data from an earlier saved point. Simple Example: If you saved a backup on July 1st and your system crashes on July 2nd , you can recover the July 1st backup because of retention.

How does Backup Retention help with Compliance?

Some industries have legal rules requiring companies to keep backups for a certain period. Simple Example: A hospital may need to keep patient data backups for 5 years to follow healthcare data retention laws.

How does Backup Retention manage Storage Space?

Retention policies automatically delete old backups after a set time to save storage space. Simple Example: If you set daily backups for 7 days, backups older than 7 days get deleted automatically.

How does Backup Retention help during Ransomware Attacks?

Retention allows you to restore data from a time before the ransomware attack happened. Simple Example: You took a backup on July 19th and on July 20th an attacker Corrupts your files, you can still bring those files back from July 19th backup.

Real-World Example of Backup Retention Policy

Imagine you’re an IT Admin: You set daily backups of company data and configure a 30-day retention policy. Each day’s backup is kept for 30 days. After 30 days, the oldest backups are automatically deleted.

What is Hyper-V?

Hyper-V is a Type 1 Hypervisor developed by Microsoft. It creates and manages Virtual Machines (VMs) on a physical server, allowing multiple OSes like Windows and Linux to run on the same hardware.

Why do we need Hyper V ?

Hyper-V is used for learning purpose as it create virtual labs for CCNA, CCNP, and for other IT trainings

It helps in quick creation and deletion of VMs without extra hardware, also it helps to consolidate multiple servers into VMs, improving efficiency and resource usage.

What is ESXi?

VMware ESXi is a Type 1 Hypervisor created by VMware. It runs directly on physical server hardware and It is part of VMware vSphere, which is used for Industry level virtualization.

Why we need ESXi?

We need ESXi as It helps to manage multiple VMs using tools like vSphere and it also stores all VM data in a central location like a Database.

Hyper-V vs ESXi

1. So, the main difference between Hyper-V and ESXi is the vendor. Hyper-V is from Microsoft, while ESXi comes from VMware.
   

2. For management tools, Hyper-V uses Hyper-V Manager or Windows Admin Center, while ESXi uses vSphere Client or vCenter.

3. One key difference is in how they work with other tools: Hyper-V works well with Windows and Microsoft tools, while ESXi is designed to work best with VMware's tools.

What is Backup?

A backup is a copy of your data saved on another server, hard drive, or cloud. It helps restore your data if it’s lost, damaged, or deleted.

Why Do We Need Backup?

To protect our sensitive data against hardware failure, human error, cyberattacks, natural disasters, and software corruption.

What is Fault Tolerance?

Fault tolerance means a system that keeps working even if a part of it fails. It is used to avoid downtime and data loss with the help of backups or redundancy (like RAID for disk space or load balancers for servers). We can think of it like a car with two engines—if one stops, the other keeps the car running.

What is a Full Backup and When we can use it?

A full backup copies all data every time it runs. It stores everything into one tape/file and is easy to manage and restore. It’s Like copying a whole movie onto one USB — plug it in once and watch it all.

We can use it for small to medium data when speed or storage is not a concern, and you need quick recovery.

Advantage of Full Backup IN HINDI

It is the easiest to restore because everything is stored in one place; you only need one restore session.

Disadvantage of Full Backup IN HINDI

It takes the longest to complete and uses the most storage, especially with large data sets.

What is Full Backup Restore

A full backup restore means recovering all your data directly from a single backup file that contains everything. Since the full backup is a complete copy of the system at that point in time, you don’t need any other backups to restore — just that one full backup.

What is an Incremental Backup?

Incremental Backup Backs up only those files that changed since the last backup (either full or incremental), saving time and space.

You do a full backup on Monday.

On Tuesday, instead of backing up everything again, you only back up the files that changed since Monday.

By Wednesday, you only back up what changed since Tuesday, and so on.

Main Advantage of Incremental Backup in Hindi

The main advantage of incremental backups are storage-efficient as they use less storage and they are fast in backup up data because they only save the data that has changed since the last backup.

What is Incremental Restore?

Incremental restore means recovering data by first restoring the full backup, then restoring each incremental backup in sequence and in the correct order, until the system is fully restored.

Main DisAdvantage of Incremental Backup IN HINDI

One of the Major Disadvantage is that it’s Restoring takes longer because it needs to process the full backup plus every incremental backup in an sequence. If even one backup in the chain is missing or corrupted, the recovery may fail.

What is a Differential Backup?

A Differential Backup Backs up all the changes made since the last full backup, not just from the last day.

Suppose you take a full backup on Monday. On Tuesday, the differential backup includes all changes since Monday. On Wednesday, it again saves all changes since Monday, and this continues each day.

Differential backups keep growing and saving such changes until the next full backup is taken, after which this same cycle restarts.

Restore Process for Differential Backup

To restore through Differential Backup, you only need the last full backup and the latest differential backup. This will recover everything.

Like Suppose, If the system crashes on Saturday, restore using Monday’s full backup and Friday’s differential backup.