About Me
CompTIA Server+
1 Server Hardware
1-1 Server Types
1-1 1 Rack Servers
1-1 2 Tower Servers
1-1 3 Blade Servers
1-1 4 Micro Servers
1-1 5 Hyper-converged Infrastructure
1-1 6 Virtual Servers
1-2 Server Components
1-2 1 CPUs
1-2 2 Memory (RAM)
1-2 3 Storage Devices
1-2 4 Power Supply Units (PSUs)
1-2 5 Cooling Systems
1-2 6 Network Interface Cards (NICs)
1-2 7 Batteries and Uninterruptible Power Supplies (UPS)
1-2 8 Chassis and Enclosures
1-3 Server Form Factors
1-3 1 ATX
1-3 2 EATX
1-3 3 MicroATX
1-3 4 Mini-ITX
1-3 5-1U, 2U, 4U
1-4 Server Management
1-4 1 Remote Management Interfaces
1-4 2 Out-of-Band Management
1-4 3 In-Band Management
1-4 4 KVM (Keyboard, Video, Mouse) Switches
1-4 5 Serial Console
2 Server Virtualization
2-1 Virtualization Concepts
2-1 1 Hypervisors
2-1 2 Type 1 Hypervisors
2-1 3 Type 2 Hypervisors
2-1 4 Virtual Machines (VMs)
2-1 5 Virtual Disks
2-1 6 Virtual Networking
2-2 Virtualization Platforms
2-2 1 VMware vSphere
2-2 2 Microsoft Hyper-V
2-2 3 Citrix XenServer
2-2 4 KVM (Kernel-based Virtual Machine)
2-3 Virtual Machine Management
2-3 1 VM Creation
2-3 2 VM Configuration
2-3 3 VM Migration
2-3 4 VM Cloning
2-3 5 VM Snapshots
2-4 Resource Management
2-4 1 CPU Allocation
2-4 2 Memory Allocation
2-4 3 Storage Allocation
2-4 4 Network Allocation
3 Server Storage
3-1 Storage Technologies
3-1 1 Direct-Attached Storage (DAS)
3-1 2 Network-Attached Storage (NAS)
3-1 3 Storage Area Network (SAN)
3-1 4 Object Storage
3-1 5 Cloud Storage
3-2 Storage Protocols
3-2 1 SCSI (Small Computer System Interface)
3-2 2 SATA (Serial Advanced Technology Attachment)
3-2 3 SAS (Serial Attached SCSI)
3-2 4 iSCSI (Internet Small Computer System Interface)
3-2 5 Fibre Channel
3-2 6 NFS (Network File System)
3-2 7 SMBCIFS (Server Message BlockCommon Internet File System)
3-3 RAID (Redundant Array of Independent Disks)
3-3 1 RAID 0
3-3 2 RAID 1
3-3 3 RAID 5
3-3 4 RAID 6
3-3 5 RAID 10
3-3 6 RAID Levels Comparison
3-4 Storage Management
3-4 1 Disk Partitioning
3-4 2 File Systems
3-4 3 Volume Management
3-4 4 Backup and Recovery
3-4 5 Data Deduplication
4 Server Networking
4-1 Network Protocols
4-1 1 TCPIP
4-1 2 DNS (Domain Name System)
4-1 3 DHCP (Dynamic Host Configuration Protocol)
4-1 4 HTTPHTTPS
4-1 5 FTP (File Transfer Protocol)
4-1 6 SMTP (Simple Mail Transfer Protocol)
4-1 7 SNMP (Simple Network Management Protocol)
4-2 Network Configuration
4-2 1 IP Addressing
4-2 2 Subnetting
4-2 3 VLANs (Virtual Local Area Networks)
4-2 4 Routing
4-2 5 Firewall Configuration
4-3 Network Services
4-3 1 Web Servers
4-3 2 Mail Servers
4-3 3 File Servers
4-3 4 Print Servers
4-3 5 Database Servers
4-4 Network Security
4-4 1 Encryption
4-4 2 Authentication
4-4 3 Access Control
4-4 4 Intrusion Detection and Prevention
4-4 5 VPN (Virtual Private Network)
5 Server Maintenance and Troubleshooting
5-1 Hardware Maintenance
5-1 1 Component Replacement
5-1 2 Firmware Updates
5-1 3 Driver Updates
5-1 4 Regular Cleaning
5-2 Software Maintenance
5-2 1 Operating System Updates
5-2 2 Application Updates
5-2 3 Patch Management
5-2 4 Backup Procedures
5-3 Troubleshooting Techniques
5-3 1 Diagnostic Tools
5-3 2 Error Logs
5-3 3 System Monitoring
5-3 4 Performance Tuning
5-4 Disaster Recovery
5-4 1 Backup Strategies
5-4 2 Restore Procedures
5-4 3 Failover and Failback
5-4 4 Business Continuity Planning
6 Server Security
6-1 Security Concepts
6-1 1 Confidentiality
6-1 2 Integrity
6-1 3 Availability
6-2 Security Measures
6-2 1 Physical Security
6-2 2 Network Security
6-2 3 Data Encryption
6-2 4 User Authentication
6-2 5 Role-Based Access Control (RBAC)
6-3 Security Protocols
6-3 1 SSLTLS
6-3 2 SSH (Secure Shell)
6-3 3 IPSec
6-3 4 Kerberos
6-4 Security Best Practices
6-4 1 Regular Audits
6-4 2 Security Policies
6-4 3 Incident Response
6-4 4 Compliance
7 Server Administration
7-1 User Management
7-1 1 User Accounts
7-1 2 Group Management
7-1 3 Permissions and Access Rights
7-1 4 Password Policies
7-2 System Configuration
7-2 1 Time and Date Settings
7-2 2 Network Configuration
7-2 3 Resource Allocation
7-2 4 Service Management
7-3 Monitoring and Reporting
7-3 1 Performance Monitoring
7-3 2 Resource Utilization
7-3 3 Event Logs
7-3 4 Reporting Tools
7-4 Automation and Scripting
7-4 1 Task Automation
7-4 2 Scripting Languages
7-4 3 Configuration Management Tools
8 Server Compliance and Standards
8-1 Industry Standards
8-1 1 ISO Standards
8-1 2 ITIL (Information Technology Infrastructure Library)
8-1 3 COBIT (Control Objectives for Information and Related Technologies)
8-2 Regulatory Compliance
8-2 1 GDPR (General Data Protection Regulation)
8-2 2 HIPAA (Health Insurance Portability and Accountability Act)
8-2 3 PCI DSS (Payment Card Industry Data Security Standard)
8-3 Best Practices
8-3 1 Documentation
8-3 2 Change Management
8-3 3 Risk Management
8-3 4 Continuous Improvement
6-1-3 Availability Explained

6-1-3 Availability Explained

Key Concepts

Availability Definition

Availability refers to the ability of a system, service, or network to be operational and accessible when needed. It is often expressed as a percentage, indicating the proportion of time the system is functioning correctly.

Uptime and Downtime

Uptime is the period during which a system is operational and accessible. Downtime, conversely, is the period during which the system is unavailable. High availability aims to maximize uptime and minimize downtime.

Service Level Agreements (SLAs)

SLAs are contracts between service providers and customers that define the level of service expected from the provider. They often include specific availability targets, such as 99.9% uptime, and may specify penalties for failing to meet these targets.

High Availability (HA) Strategies

High Availability strategies are designed to ensure that systems remain operational even in the face of hardware failures, software bugs, or other disruptions. Common strategies include clustering, load balancing, and redundant systems.

Redundancy and Failover

Redundancy involves duplicating critical components to ensure that if one fails, another can take over. Failover is the process of switching to a redundant or standby system when the primary system fails. Together, they enhance system availability.

Examples and Analogies

Think of availability as the reliability of a car. Uptime is the time the car is running smoothly, while downtime is when it breaks down. An SLA is like a warranty that guarantees the car will run for a certain number of miles without issues.

High Availability strategies are like having a backup car. If your primary car breaks down, you can switch to the backup. Redundancy is like having two engines in your car, so if one fails, the other keeps the car running.

© 2024 Ahmed Baheeg Khorshid. All rights reserved.