This free CompTIA Server+ study guide walks through every content domain the Server+ (SK0-005) exam tests, organized to the current CompTIA exam objectives.[1]
It’s interactive, not a wall of text: every module has built-in checkpoint quizzes, flashcards, and practice questions, so you learn by doing — not just reading.
The Server+ tests four official domains, and we teach them as four study modules, leading with the heaviest-weighted content (Server Administration and Troubleshooting together are well over half the exam). Read a module, test yourself at each checkpoint, then drill gaps with our free practice test and flashcards. This guide is a high-yield overview that maps the official content — not a full server-administration textbook.
CompTIA Server+ is one of the 14 CompTIA certifications — explore our CompTIA study guides to compare and prep across the whole family.
Server+ Exam Snapshot
| Detail | Server+ Exam |
|---|---|
| Exam code | SK0-005 (current; no SK0-006 exists) |
| Questions | Maximum of 90 (multiple choice + performance-based) |
| Time | 90 minutes |
| Passing score | 750 on a 100–900 scale (scaled score, not a percentage) |
| Certifying body | CompTIA |
| Cost | About $358–$390 (single voucher; varies by region/promo) |
| Prerequisites | None required (CompTIA A+ and ~2 years' experience recommended) |
| Validity | 3 years (Continuing Education program, since Oct 1, 2025) |
| Renewal | Earn CEUs over 3 years, or pass a higher CompTIA cert |
The Server+ covers four domains. Two of them — Server Administration and Troubleshooting — together make up well over half the exam (58%), so that is where to invest first.[1] Study by weight:
Module 1 · Server Hardware Installation & Management
One official domain, 18% of the exam. This is the physical foundation — the chassis, the disks, and the power and cooling that keep a server alive. RAID alone earns a large share of the questions here and in the troubleshooting domain, so master it cold.
1.1 Form Factors, Racking & Components
A server’s is its physical shape. A tower stands alone like a desktop; a rack-mount server bolts into a standard 19-inch rack and is measured in rack units (a is 1.75 inches); and a slides into a shared enclosure that supplies common power, cooling, and networking.[1]
Tower
Standalone upright chassis like a desktop. Easy to deploy in small offices; uses floor space and doesn't rack-densely.
Best for: Small office, branch, first server
Rack-mount (1U–4U)
Bolts into a standard 19-inch rack, sized in rack units (1U = 1.75 in). Maximizes density and cabling order in a data center.
Best for: Data centers, server rooms
Blade
A thin server module that slides into a shared enclosure providing common power, cooling, and networking to many blades.
Best for: High-density, scalable compute
Inside, servers differ from desktops in their emphasis on reliability and redundancy: multiple CPU sockets for multiprocessing, that corrects single-bit errors, redundant power supplies and fans, host bus adapters (HBAs) for storage, and a for out-of-band management. Good racking practice — rail kits, cable management, and a hot-aisle/cold-aisle layout — keeps airflow and serviceability sane.
| Form factor | Description | Best for |
|---|---|---|
| Tower | Standalone upright chassis like a desktop | Small office, branch, first server |
| Rack-mount (1U–4U) | Bolts into a 19-inch rack; sized in rack units | Data centers, server rooms |
| Blade | Thin module in a shared enclosure (power/cooling/network) | High-density, scalable compute |
1.2 RAID Levels
combines multiple disks for speed, redundancy, or both — and it is the single most-tested topic on the exam. You must know each level’s minimum drives, fault tolerance, and usable capacity by heart.[1]
stripes for pure speed with no protection; mirrors two drives; stripes with single parity (survives one failure); adds double parity (survives two); and mirrors then stripes for both speed and resilience. A can rebuild an array automatically when a member fails.
| RAID | Method | Min drives | Survives | Usable capacity |
|---|---|---|---|---|
| 0 | Striping | 2 | Nothing | 100% (n drives) |
| 1 | Mirroring | 2 | 1 drive | 50% (n / 2) |
| 5 | Stripe + single parity | 3 | 1 drive | (n − 1) drives |
| 6 | Stripe + double parity | 4 | 2 drives | (n − 2) drives |
| 10 | Mirror + stripe (1+0) | 4 | 1 per mirror pair | 50% (n / 2) |
1.3 Storage, Power & Cooling
Beyond local RAID, servers reach storage three ways. attaches disks directly to one server; shares files over the LAN (SMB/CIFS, NFS); and a presents block storage over a dedicated high-speed network, often using over Ethernet or Fibre Channel.[6]
DAS · Block-level
Direct-Attached Storage
Disks attached directly to one server (internal or external SAS). Simple and fast, but not easily shared.
NAS · File-level
Network-Attached Storage
A file server shared over the LAN using SMB/CIFS or NFS. Easy file sharing for many clients.
SAN · Block-level
Storage Area Network
Block storage over a dedicated high-speed network (Fibre Channel or iSCSI). High performance and scalability.
Power and cooling keep it all running. Use redundant, hot-swappable power supplies on separate circuits, a for graceful shutdown during outages, and managed PDUs for remote control. Watch drive interfaces too: SAS (fast, enterprise), SATA (capacity), and NVMe (lowest-latency SSD over PCIe).
| Type | Access level | Transport | Use |
|---|---|---|---|
| DAS | Block | Internal disks / external SAS | Single-server, simple, fast |
| NAS | File | LAN (SMB/CIFS, NFS) | Shared files for many clients |
| SAN | Block | Fibre Channel / iSCSI | High-performance shared block storage |
Checkpoint · Server Hardware Installation & Management
Question 1 of 10
Which type of RAID configuration is characterized by striping with distributed parity?
Module 2 · Server Administration
One official domain, 30% of the exam — the single heaviest. This is where you operate the server day to day: install and configure the OS and its roles, run virtual machines, and design for availability. Expect performance-based questions here.
2.1 Server Roles & the OS
A is the primary job a server does — file, print, web, database, DNS, DHCP, or directory services. After installing the OS (Windows Server or a Linux distribution), you configure roles to requirements, harden the build, and join it to like Active Directory for centralized authentication.[8]
Manage servers remotely with SSH (Linux, TCP 22) or RDP (Windows, TCP 3389), keep clocks synced with NTP, and automate repetitive work with shell, PowerShell, or Bash scripting so configuration is consistent at scale.
| Role | What it provides |
|---|---|
| File / print | Shared storage and print services for clients |
| Web | Hosts websites and web applications (HTTP/HTTPS) |
| Database | Stores and serves structured data (SQL/NoSQL) |
| DNS | Resolves hostnames to IP addresses |
| DHCP | Automatically assigns IP, mask, gateway, and DNS |
| Directory (AD/LDAP) | Centralized identity, authentication, and policy |
2.2 Virtualization & Containers
Virtualization is a major theme of this domain. A abstracts physical hardware so many run on one host. A Type 1 (bare-metal) hypervisor runs directly on hardware for production; a Type 2 (hosted) hypervisor runs as an app on an OS for labs.[5]
A is lighter than a VM — it packages an app and its dependencies but shares the host kernel, so it starts in seconds. Use to roll back a VM after a change (but never as a real backup), and to allocate disk on demand.
| Aspect | Virtual machine | Container |
|---|---|---|
| Isolation | Full guest OS on a hypervisor | Shares the host OS kernel |
| Size / startup | Larger; boots in minutes | Tiny; starts in seconds |
| Best for | Strong isolation, different OSes | Lightweight, scalable microservices |
2.3 High Availability & Clustering
means designing so a single failure doesn’t take a service down. links multiple nodes so they act as one system: a failover cluster shifts a failed node’s workload to a survivor, while load balancing spreads requests for performance. keeps a current copy of data on another node or site.
| Technique | What it does |
|---|---|
| Failover cluster | Another node takes over a failed node's workload |
| Load balancing | Distributes requests across nodes for performance |
| Replication (sync/async) | Keeps a current data copy on another node/site |
| NIC teaming | Bonds NICs for bandwidth and link redundancy |
| Redundant power | Dual PSUs on separate circuits + UPS |
2.4 Maintenance & Documentation
Sustained operations rest on discipline. Run on a schedule (test, then deploy OS and firmware updates), establish a performance so you can spot drift, and keep thorough documentation — diagrams, asset and license inventories, and change records. A formal change process reduces the human error behind most outages.
Checkpoint · Server Administration
Question 1 of 10
Which technology is primarily used in servers to enable virtualization?
Module 3 · Security & Disaster Recovery
One official domain, 24% of the exam. This domain pairs keeping a server secure with being able to recover it after a disaster — two sides of protecting the business’s data and uptime.
3.1 Security & Hardening
shrinks the attack surface: remove unused roles and services, close unnecessary ports, patch promptly, and enforce and . Protect data with encryption at rest and in transit, and anchor key protection in an or a . Secure the physical layer too — locked racks, access control, and proper data destruction when media retires.[4]
| Control | Why it matters |
|---|---|
| Remove unused roles/services | Fewer running services = smaller attack surface |
| Patch OS and firmware | Closes known vulnerabilities before exploitation |
| Least privilege + RBAC | Limits damage from a compromised account |
| MFA | Stops most credential-theft attacks |
| Encryption (rest + transit) | Protects data if media or traffic is captured |
| Secure data destruction | Prevents recovery of retired media (NIST SP 800-88) |
3.2 Backups
Backups are the core of recoverability. A copies everything; an copies only what changed since the last backup of any type (small, but a restore needs the full plus every increment); a copies what changed since the last full (larger, but restores from just the full plus the latest differential).[3] Follow the and keep an air-gapped copy against ransomware — and always test restores.
Full backup
Incremental backup
Differential backup
3.3 Disaster Recovery
Disaster recovery planning starts with two numbers: (how fast you must recover) and (how much data loss is acceptable). They size everything else — backup frequency and the alternate-site tier.[3]
RPO — Recovery Point Objective
Looks backward from the outage: how much data loss is acceptable. Drives backup frequency (a 1-hour RPO needs at least hourly backups/replication).
RTO — Recovery Time Objective
Looks forward from the outage: how fast service must be restored. Drives the DR site tier and failover design (hot vs. warm vs. cold).
Alternate sites trade cost for speed: a can take over almost instantly, a needs data restored and services started, and a is just space and power. switches to the redundant system, and returns to the primary once it’s repaired. Track reliability with and repair speed with .
- 1
Hot site · Minutes · Highest cost
Fully equipped and continuously synced with live data. Can take over almost immediately — the lowest RTO.
- 2
Warm site · Hours to a day · Moderate cost
Hardware, software, and connectivity in place, but data must be restored and services started before takeover.
- 3
Cold site · Days · Lowest cost
Just space, power, and cooling. Equipment and data must be brought in and built up before it can run — the highest RTO.
| Term | Meaning |
|---|---|
| RTO | Maximum acceptable time to restore service (drives site tier) |
| RPO | Maximum acceptable data loss (drives backup frequency) |
| Hot / warm / cold site | Alternate sites from instant takeover to space-only |
| Failover / failback | Switch to redundant system; return to primary when fixed |
| MTTR / MTBF | Mean time to repair / mean time between failures |
Checkpoint · Security & Disaster Recovery
Question 1 of 10
What is the primary purpose of a Hardware Security Module (HSM) in a server environment?
Module 4 · Troubleshooting
One official domain, 28% of the exam. Server+ rewards a disciplined process and knowing which symptom points to which fault — across hardware, storage, the OS, the network, and security. Expect performance-based questions here.
4.1 The Troubleshooting Methodology
CompTIA tests an exact, ordered . Knowing the order — and that you verify and document last, and never implement a fix before testing your theory — is one of the most reliable sets of points on the exam.[1]
- 1
Identify the problem
Gather information, question users, identify symptoms, and determine if anything recently changed.
- 2
Establish a theory of probable cause
Question the obvious; consider multiple possibilities (hardware, OS, network, storage, security).
- 3
Test the theory to determine cause
If confirmed, move on. If not, establish a new theory or escalate.
- 4
Establish a plan of action
Plan the resolution and identify potential effects of the fix on the system and users.
- 5
Implement the solution or escalate
Apply the fix — or escalate to someone with more access or expertise.
- 6
Verify full system functionality
Confirm the fix works and, if applicable, implement preventive measures.
- 7
Document findings, actions & outcomes
Record the cause, the solution, and lessons learned for next time.
4.2 Hardware & Storage Issues
Hardware faults often show at boot. A failed signals a problem — read beep/POST codes, reseat RAM and cards, and check power.
Storage problems include a (a RAID set running on a failed member — replace and rebuild fast), warnings predicting a disk failure, and capacity exhaustion. Overheating from failed fans or blocked airflow can throttle or shut down a server.
| Symptom | Likely cause | First action |
|---|---|---|
| No POST / beep codes | Bad RAM, card, or power | Read codes; reseat RAM and cards |
| Array degraded | A RAID member failed | Replace the drive; let it rebuild |
| SMART warnings | A disk is failing | Back up, then replace the drive |
| Thermal shutdown | Failed fan or blocked airflow | Check cooling, dust, and fans |
| Disk full | Logs/data filled the volume | Find large files; expand or archive |
4.3 OS, Network & Performance
Above the hardware, the usual suspects are services, the network, and performance. A crash (Windows BSOD or Linux kernel panic) and event logs point to drivers, corruption, or hardware.
Network problems trace through cabling, NIC config, IP settings, and DNS — if you can ping by IP but not by name, suspect DNS. Performance issues come down to one bottleneck: CPU, memory, disk I/O, or network, found by comparing usage to the .
Checkpoint · Troubleshooting
Question 1 of 10
What is the first step in troubleshooting a server that fails to boot with no error messages or beeps?
How to Use This Server+ Study Guide
This guide is built to be worked, not just read. The most efficient path to a pass:
- Study by weight. Server Administration (30%) and Troubleshooting (28%) are well over half the exam — start there, then Security & Disaster Recovery (24%) and Hardware (18%).
- Master RAID and DR first. RAID levels and the disaster-recovery concepts (backup types, RTO/RPO, hot/warm/cold sites) appear throughout the exam — know them cold.
- Check off as you go. Use the Study Guide Contents to mark each section done; it raises your exam-readiness score.
- Take every checkpoint. The end-of-module quizzes show exactly which domains need another pass.
- Drill the weak domain. Send your weak area into the flashcards and a practice test until the score climbs.
- Practice the PBQs. Performance-based questions reward hands-on skill — walk through RAID math, a backup restore order, and the troubleshooting steps until they’re automatic.
Server+ Concept Questions
Common Server+ concepts candidates search while studying — each answered briefly and backed by an official source. Test yourself, then drill them as flashcards.
Server+ Glossary
The high-yield Server+ terms in one place — hover any dotted term in the guide, or flip the whole deck here as a self-grading flashcard set.
- 3-2-1 rule
- Keep 3 copies of data, on 2 different media types, with 1 copy offsite, to survive most failure and disaster scenarios.
- Baseline
- A documented record of normal performance (CPU, memory, disk, network) used to detect abnormal behavior later.
- Blade server
- A stripped-down server module that slides into a shared enclosure providing common power, cooling, and networking to many blades.
- BMC / IPMI
- Baseboard Management Controller using IPMI — out-of-band management for remote power, console, and sensor monitoring, independent of the OS.
- Clustering
- Linking multiple servers (nodes) to act as one system for availability or load balancing; a failed node's load shifts to others.
- Cold site
- A basic facility (space, power, cooling) with no ready equipment; cheapest but slowest to bring online.
- Container
- A lightweight, isolated package of an application and its dependencies that shares the host OS kernel; smaller and faster than a VM.
- DAS
- Direct-Attached Storage — disks connected directly to one server (internal or external SAS); simple and fast but not easily shared.
- Degraded array
- A fault-tolerant RAID set running with a failed member: still operational but unprotected until the drive is replaced and rebuilt.
- Differential backup
- Backs up data changed since the last full backup; larger than incremental, but restores from just the full plus the latest differential.
- Directory services
- A centralized identity store (e.g., Active Directory, LDAP) for authentication, authorization, and resource management.
- ECC memory
- Error-Correcting Code RAM that detects and corrects single-bit memory errors; standard in servers for data integrity.
- Failback
- Returning operations to the primary system or site once it is repaired and verified after a failover.
- Failover
- Automatically switching to a redundant system or site when the primary fails, to maintain availability.
- Form factor
- The physical size and shape of a server — tower, rack-mount (sized in rack units), or blade — chosen for density, scalability, and environment.
- Full backup
- A complete copy of all selected data; slowest and largest to create, but the fastest and simplest to restore.
- Hardening
- Reducing a server's attack surface by removing unused services/roles, closing ports, patching, and applying secure baselines.
- High availability (HA)
- Designing systems with redundancy and failover so services keep running despite component failures.
- Hot site
- A fully equipped, continuously updated alternate site that can take over almost immediately — fastest recovery, highest cost.
- Hot spare
- A standby drive that automatically rebuilds a RAID array when a member fails, minimizing the unprotected window.
- Hot-swappable
- A component (drive, power supply, fan) that can be replaced while the server is powered on, with no downtime.
- HSM
- Hardware Security Module — a tamper-resistant device that securely generates, stores, and uses cryptographic keys, and accelerates crypto.
- Hypervisor
- Software that creates and runs virtual machines by abstracting physical hardware; Type 1 runs on bare metal, Type 2 on a host OS.
- Incremental backup
- Backs up only data changed since the last backup of any type; small and fast, but a restore needs the full plus every increment in order.
- iSCSI
- Internet Small Computer System Interface — SCSI block commands carried over TCP/IP, letting a SAN run on standard Ethernet.
- Least privilege
- Granting users and services only the minimum access needed, limiting damage from compromise or error.
- MFA
- Multifactor authentication — requiring two or more factors (know, have, are) to authenticate, strongly reducing credential theft risk.
- MTBF
- Mean Time Between Failures — the average operating time between failures; a measure of reliability.
- MTTR
- Mean Time To Repair — the average time to fix a failed component and restore service.
- NAS
- Network-Attached Storage — file-level storage shared over the LAN using SMB/CIFS or NFS.
- Patch management
- The scheduled process of testing and applying OS and firmware updates to fix bugs and close security holes.
- POST
- Power-On Self-Test — firmware diagnostics at boot; beep or POST codes indicate hardware faults like bad RAM or no video.
- Rack unit (U)
- A unit of vertical rack space equal to 1.75 inches (44.45 mm); a 2U server occupies two slots in a standard 19-inch rack.
- RAID
- Redundant Array of Independent Disks — combining multiple drives for performance, redundancy, or both.
- RAID 0
- Disk striping with no parity: data is split across drives for speed and full capacity, but any single drive failure loses all data.
- RAID 1
- Disk mirroring: identical copies on two drives; survives one failure, with usable capacity equal to half the raw total.
- RAID 10
- A stripe of mirrors (1+0): combines RAID 1 redundancy with RAID 0 speed; needs 4+ drives.
- RAID 5
- Striping with single distributed parity across 3+ drives; survives one drive failure with usable capacity of (n − 1) drives.
- RAID 6
- Striping with double distributed parity across 4+ drives; survives two simultaneous failures with usable capacity of (n − 2) drives.
- Replication
- Copying data to another system or site in real time or near-real time so a current copy is always available.
- RPO
- Recovery Point Objective — the maximum acceptable amount of data loss, measured as time back to the last good backup.
- RTO
- Recovery Time Objective — the maximum acceptable time to restore a service after an outage.
- SAN
- Storage Area Network — block-level storage over a dedicated high-speed network (Fibre Channel or iSCSI).
- Server role
- A primary function a server provides — file, print, web, database, DNS, DHCP, or directory services.
- SMART
- Self-Monitoring, Analysis and Reporting Technology — drive self-diagnostics that help predict disk failures before they happen.
- Snapshot
- A point-in-time capture of a VM's state for quick rollback after a change; not a substitute for a real backup.
- Thin provisioning
- Allocating storage on demand as data is written, so a volume can be presented larger than the space currently consumed.
- TPM
- Trusted Platform Module — a chip that stores keys and integrity measurements to support secure boot and full-disk encryption.
- Troubleshooting methodology
- CompTIA's 7 steps: identify the problem; theorize a cause; test it; plan; implement or escalate; verify; document.
- UPS
- Uninterruptible Power Supply — battery backup that bridges a power loss and enables a graceful shutdown.
- Virtual machine (VM)
- A software-based computer with its own virtual CPU, memory, disk, and NIC, running on a hypervisor.
- Warm site
- A partially equipped alternate site with hardware and connectivity ready, needing data restore and setup before takeover.
Server+ Study Guide FAQ
The Server+ SK0-005 exam has a maximum of 90 questions and you get 90 minutes. The questions are a mix of multiple choice (single and multiple response) and performance-based questions (PBQs) that require hands-on, scenario-style tasks.
You need a scaled score of 750 on a scale of 100 to 900. It is not a simple percentage — CompTIA converts your raw score so every exam form demands the same ability level, so don't try to estimate it as a percent correct.
Server Hardware Installation and Management (18%), Server Administration (30%), Security and Disaster Recovery (24%), and Troubleshooting (28%). Server Administration and Troubleshooting are the two heaviest domains — together well over half the exam.
It no longer lasts for life. Effective October 1, 2025, Server+ moved into CompTIA's Continuing Education program, so the SK0-005 certification is valid for three years and you renew it with continuing-education units (CEUs). Older Server+ versions were non-expiring, but that is now outdated.
A single exam voucher is roughly $358 to $390 USD (it varies by region and promotion). There are no required prerequisites, though CompTIA recommends CompTIA A+ (or equivalent knowledge) and about two years of hands-on server experience.
RAID and storage, virtualization, and the disaster-recovery concepts (backup types, RTO/RPO, and hot/warm/cold sites) are the highest-yield areas, alongside the 7-step troubleshooting methodology. Master RAID levels and DR strategy first — they appear throughout the exam and the performance-based questions.
Study by weight: lead with Server Administration (30%) and Troubleshooting (28%). Read each module, take its checkpoint quiz, then drill your weak domain with our free practice test and flashcards until your readiness score climbs.
Yes — this study guide, the module checkpoints, the glossary, the concept questions, the practice test, and the flashcards are 100% free with no account required.
Server+ is considered moderately challenging — its difficulty is breadth (hardware, RAID, virtualization, storage, security, disaster recovery, and troubleshooting) plus performance-based questions that test applied skills. Broad, organized review and lots of practice questions are the key.
References
- 1.CompTIA. “Server+ (SK0-005) Certification Exam Objectives.” comptia.org. ↑
- 2.CompTIA. “CompTIA Continuing Education (renewal & CEUs).” comptia.org. ↑
- 3.National Institute of Standards and Technology. “SP 800-34 Rev. 1 — Contingency Planning Guide for Federal Information Systems.” csrc.nist.gov. ↑
- 4.National Institute of Standards and Technology. “SP 800-88 Rev. 1 — Guidelines for Media Sanitization.” csrc.nist.gov. ↑
- 5.National Institute of Standards and Technology. “SP 800-125 — Guide to Security for Full Virtualization Technologies.” csrc.nist.gov. ↑
- 6.National Institute of Standards and Technology. “SP 800-209 — Security Guidelines for Storage Infrastructure.” csrc.nist.gov. ↑
- 7.National Institute of Standards and Technology. “SP 800-111 — Guide to Storage Encryption Technologies for End User Devices.” csrc.nist.gov. ↑
- 8.Internet Engineering Task Force. “RFC 2131 — Dynamic Host Configuration Protocol.” rfc-editor.org. ↑
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