CertiFive RAID sentences
RAID 0 stripes and dies with one disk. RAID 1 mirrors. RAID 5 loses one. RAID 6 loses two. RAID 10 is mirrors that are then striped. JBOD is not RAID.
Study guide · Flashcards & memory notes
Server+ Flashcards & Memory Notes
40 recall cards for the facts Server+ (SK0-005) keeps asking you to separate: RAID and storage, administration, backups, and the troubleshooting order.
How to use these cards: Say the answer out loud before you flip the card, and mark it honestly. Revisit the cards you missed tomorrow rather than rereading them right away. Progress is kept only while this page is open. For the full explanations behind each card, see the core notes.
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Deck 1 · Hardware and storage
Racks, RAID, shared storage, and remote management.
1.1What does 1U measure?
1.75 inches of rack height. It is not a power rating.
1.2What does RAID 0 provide?
Striping without parity. One disk failure loses the set.
1.3What does RAID 5 survive that RAID 6 also survives, and what does only RAID 6 survive?
RAID 5 survives one disk failure. RAID 6 survives two. A second failure during a RAID 5 rebuild loses the array.
1.4What is JBOD?
Disks presented without RAID redundancy. It is not a mirror.
1.5How does a NAS differ from a SAN?
NAS shares files with NFS or CIFS. A SAN presents block storage. A file share is not a LUN.
1.6How does a PDU differ from a UPS?
A PDU distributes rack power. A UPS bridges a short outage. Neither one is a generator.
1.7What is out-of-band management for?
Power and a console when the operating system is down. SSH needs a running OS.
1.8Which fiber type runs farther?
Single-mode. Multimode is the shorter run. LC is the small connector used with an SFP.
1.9What does a failed RAID cache battery often cause?
Write-back cache turns off and writes slow down. The array is not automatically erased.
1.10Which parts are hot-swappable on the objectives?
Drives, fans, and power supplies. The motherboard is not. A bay is not a hot spare until you assign the disk.
Deck 2 · Administration
Installs, names, clusters, and licenses.
2.1Which partition table boots a disk larger than 2 TB?
GPT, with UEFI. MBR stops near 2 TB and allows four primary partitions.
2.2Which filesystem is a VMware datastore?
VMFS. NTFS and ReFS are Windows. ext4 is Linux. ZFS is the pool filesystem with checksums.
2.3What does an address in 169.254.0.0/16 mean?
APIPA. No DHCP server answered. A wrong DHCP scope is a different fault: a server did answer.
2.4Which ranges are RFC 1918 private IPv4 space?
10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. 169.254.0.0/16 is APIPA, not RFC 1918.
2.5How do active-active and active-passive clusters differ?
Active-active serves on more than one node. Active-passive keeps a node waiting. Failback returns the service to the original node.
2.6What is a cluster heartbeat?
The check that a node is still alive. Two powered-on servers without it are not a working cluster.
2.7What is overprovisioning?
Assigning more virtual CPU or memory than the host physically has. It fails when every guest peaks at once.
2.8How do bridged and NAT virtual networks differ?
Bridged puts the guest on the physical LAN. NAT hides it behind the host.
2.9How do per-core and per-socket licenses differ?
Per-core counts cores. Per-socket counts populated CPU sockets. A true-up reconciles what you run with what you bought.
2.10What can a hosts file do to DNS?
Override the name on that one machine. A stale entry sends the name to an old address even when DNS is right.
Deck 3 · Security and recovery
Backups, sites, identity, and media destruction.
3.1How do incremental and differential backups differ?
Incremental copies changes since the last backup. Differential copies changes since the last full. Restoring incrementals needs every one of them, in order.
3.2How do RPO and RTO differ?
RPO is how much data you can lose. RTO is how long until the service returns.
3.3How do a hot site and a cold site differ?
A hot site is ready to run. A cold site is space and power. A warm site sits between them.
3.4How do synchronous and asynchronous replication differ?
Synchronous waits until both sides store the write. Asynchronous acknowledges locally first. Async can lose more data.
3.5Why is a snapshot on the same array not a disaster copy?
If that array dies, the snapshot dies with it. An off-site backup is a different copy.
3.6What makes authentication multifactor?
Two different factor types: know, have, or are. Two passwords are still one factor.
3.7What does degaussing erase, and what does it miss?
It erases magnetic disks and tape. It does not reliably erase an SSD. Shred, crush, or incinerate the solid-state media.
3.8How does a mantrap differ from a bollard?
A mantrap admits one person between two doors. Bollards stop vehicles.
3.9What does a system-state backup include that a file copy does not?
Boot files, the registry, and a domain controller's directory database. User documents are a file-level backup.
3.10What is segregation of duties?
The person who requests a change is not the only person who approves it.
Deck 4 · Troubleshooting
The order, the screens, and the commands.
4.1What do you do before you start swapping parts?
Identify the problem and test a theory. Then make one change and verify it.
4.2Which crash screen belongs to Windows, ESXi, and Linux?
Blue is Windows. Purple is VMware ESXi. A kernel panic is Linux.
4.3What does a failed CMOS battery cause?
Lost firmware settings and the wrong clock. It is not a RAID parity error.
4.4What does clock skew break, and what fixes it?
Domain logon can fail even with the right password. NTP corrects the clock.
4.5How do "unknown host" and "destination unreachable" differ?
Unknown host is a name lookup failure. Destination unreachable is a routing problem.
4.6A new server shows 169.254.12.8. What failed?
DHCP did not answer. An address from the wrong live scope is a different fault.
4.7A Linux file is allowed by Unix permissions and still denied. What do you check?
SELinux or another mandatory control. Opening the file to mode 777 is the wrong fix.
4.8Why is a RAID 5 rebuild riskier than a RAID 6 rebuild?
A second disk failure during a RAID 5 rebuild loses the array. RAID 6 can survive that second failure.
4.9Which tool shows a Windows address, and which tool asks DNS?
ipconfig shows the address. dig or nslookup asks DNS. ping tests reachability.
4.10When do you write the root-cause report if users are down?
After you restore and verify the service. The report does not come before the fix.
Memory notes
Groupings that make the highest-yield Server+ facts easier to recall.
Three backup restores
A full stands alone. A differential needs the full and the latest differential. An incremental needs the full and every later incremental, in order. A snapshot on the same shelf is not the off-site copy.
Two recovery clocks
RPO is data you can lose. RTO is time until service. Hot is ready. Cold is a room. Synchronous waits for both sites. Asynchronous does not.
Three crash names
Blue screen, Windows. Purple screen, ESXi. Kernel panic, Linux. POST happens before any of them. A CMOS battery loses the clock.
Name versus path
169.254 means DHCP was silent. Unknown host means DNS failed. Destination unreachable means routing failed. A hosts file can lie on one machine.
One change
Identify, theorize, test, plan, change one thing, verify, then write the cause. Reverse a change that did not help. Document as you go.
Continue the Server+ study path
Test what you have learned with a timed practice exam.
Overview
Exam format, the 750 passing score, four domain weights, and the October 2025 continuing-education change.
Core Notes
Reference notes for racking and RAID, administration, backups, and the troubleshooting order.
Flashcards & Memory Notes
40 recall cards in four decks, plus memory notes for RAID, backups, and recovery sites.
Practice Exams
200 original questions with custom exams, explanations, and an unofficial score on the 100-900 scale.
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