CompTIA Server+: key terms

Flashcards for this exam CompTIA Server+ guide

• /etc/fstabThe Linux file that lists filesystems to mount automatically at boot, with their devices, mount points, types and options.Foundational
• /var DirectoryThe Linux directory for variable data that changes during operation, including logs, spool files, caches and databases.Foundational
• 2N RedundancyA design with two fully independent systems, each able to carry the entire load, so one whole system can fail.Intermediate
• 3-2-1 Backup RuleA backup guideline: keep three copies of data on two different media types with one copy offsite.Foundational
• Active Directory Domain Services (AD DS)Microsoft's on-premises directory service that stores users, computers and groups and provides authentication and policy for Windows domains.Foundational
• Air-Gapped BackupA backup copy that is physically or logically isolated from production networks so attackers cannot reach it.Intermediate
• Aisle ContainmentPhysically enclosing hot aisles or cold aisles with doors, panels or roofs to prevent mixing of hot and cold air.Intermediate
• Application-Consistent BackupA backup taken after the application flushes buffers and pauses writes so data is in a recoverable, transactionally consistent state.Intermediate
• ASHRAE Thermal GuidelinesASHRAE TC 9.9 recommendations for data center temperature and humidity, with a recommended inlet range of 18-27 degrees C.Intermediate
• Asymmetric Logical Unit Access (ALUA)A SCSI standard by which a storage array reports which paths to a LUN are active-optimized versus active-non-optimized.Advanced
• Automatic Transfer Switch (ATS)A switch that automatically transfers electrical load from a failed utility source to a backup source such as a generator.Intermediate
• Backup GeneratorAn engine-driven generator, typically diesel, that supplies long-duration power to a facility during utility outages.Foundational
• Backup WindowThe period during which backups are allowed to run without disrupting production workloads.Foundational
• Baseboard Management Controller (BMC)A dedicated microcontroller on a server motherboard that provides out-of-band monitoring and management independent of the OS.Foundational
• Blade ServerA thin, modular server that slides into a shared chassis providing power, cooling, networking and management.Foundational
• Block StorageStorage that presents raw volumes divided into fixed-size blocks to an operating system, which formats them with a file system.Foundational
• Changed Block Tracking (CBT)A hypervisor feature that records which disk blocks changed since a point in time so backups copy only changed blocks.Advanced
• Cluster QuorumThe voting mechanism a failover cluster uses to decide whether enough nodes are communicating to keep running and avoid split-brain.Intermediate
• Computer Room Air Conditioner (CRAC)A precision cooling unit using a refrigerant compressor to cool data center air; contrasted with a CRAH, which uses chilled water.Intermediate
• CronA time-based job scheduler and its five-field schedule syntax (minute, hour, day of month, month, day of week).Foundational
• Data Center Infrastructure Management (DCIM)Software that monitors and manages data center physical infrastructure such as power, cooling, space and assets.Intermediate
• Data DeduplicationA storage efficiency technique that eliminates duplicate data blocks or segments, storing only one copy and references to it.Intermediate
• Device Mapper Multipath (DM-Multipath)A Linux feature that combines multiple I/O paths to a SAN LUN into one device for redundancy and load balancing.Advanced
• DHCP FailoverA Windows Server DHCP feature where two servers share lease information for a scope in load-balance or hot-standby mode.Intermediate
• Differential BackupA backup that copies all data changed since the last full backup, growing each day until the next full.Foundational
• Direct-Attached Storage (DAS)Storage connected directly to a single server, such as internal drives or an external SAS enclosure, without a network.Foundational
• dmesgA Linux command that prints the kernel ring buffer containing hardware detection, driver and kernel messages.Foundational
• Domain Controller (DC)A Windows Server running AD DS that authenticates users and computers and holds a writable or read-only copy of the directory.Foundational
• Erasure CodingA data protection method that splits data into fragments with parity fragments distributed across nodes or drives, rebuilding from any sufficient subset.Advanced
• Error-Correcting Code Memory (ECC)Server RAM that detects and corrects single-bit memory errors and detects multi-bit errors, improving reliability.Foundational
• Event ViewerThe Windows console for viewing System, Application, Security and other event logs.Foundational
• ext4The fourth extended filesystem, a mature journaling filesystem that is the default on many Debian and Ubuntu Linux systems.Foundational
• Failover ClusteringA Windows Server feature that groups servers (nodes) so clustered roles automatically fail over to another node when one fails.Intermediate
• Fibre Channel (FC)A high-speed, lossless storage networking protocol that carries block SCSI or NVMe traffic between servers and storage arrays.Intermediate
• Fibre Channel ZoningFabric-level access control that defines which FC devices can communicate with each other.Intermediate
• Filesystem Hierarchy Standard (FHS)The standard that defines the directory layout and purpose of top-level directories on Linux and Unix-like systems.Foundational
• Flexible Single Master Operation (FSMO)Five special AD roles held by specific domain controllers to perform operations that cannot be multi-master.Intermediate
• fsckThe Linux filesystem consistency check and repair utility, run on unmounted filesystems.Foundational
• Full BackupA backup that copies all selected data regardless of when it last changed.Foundational
• Grandfather-Father-Son Rotation (GFS)A backup retention scheme using daily (son), weekly (father) and monthly (grandfather) backup sets.Foundational
• Group Policy Object (GPO)A collection of settings in Active Directory that configures users and computers when linked to sites, domains or OUs.Foundational
• GUID Partition Table (GPT)A modern disk partitioning scheme, part of the UEFI specification, supporting disks over 2 TiB and up to 128 partitions by default.Foundational
• Hardware RAID ControllerA dedicated adapter that implements RAID on its own processor, offloading parity calculation and often providing protected write cache.Intermediate
• Hardware-Assisted VirtualizationCPU extensions, such as Intel VT-x and AMD-V, that let hypervisors run guests efficiently and securely.Foundational
• Host Bus Adapter (HBA)An adapter that connects a server to a storage network or devices, most commonly a Fibre Channel HBA or a SAS HBA.Foundational
• Hot Aisle/Cold AisleA rack layout in which rows face alternately so equipment intakes share cold aisles and exhausts share hot aisles.Foundational
• Hot SpareAn idle standby drive in a storage array that automatically replaces a failed member and triggers a rebuild.Foundational
• Hot-SwappableA component that can be removed and replaced while the system is running without powering it down.Foundational
• HPE Integrated Lights-Out (iLO)HPE's BMC for ProLiant and Synergy servers offering remote console, virtual media, health monitoring and firmware management.Foundational
• Hyper-VMicrosoft's Type 1 hypervisor built into Windows Server and Windows client editions.Foundational
• Hyperconverged Infrastructure (HCI)An architecture combining compute, storage and virtualization on standard servers, with software-defined storage pooled across nodes.Foundational
• HypervisorSoftware that creates and runs virtual machines by abstracting physical CPU, memory, storage and network resources.Foundational
• Immutable BackupA backup that cannot be modified or deleted for a defined retention period, even by administrators.Intermediate
• Incremental BackupA backup that copies only data changed since the last backup of any type, minimizing backup time and storage.Foundational
• InodeA filesystem data structure storing a file's metadata (owner, permissions, timestamps, block pointers) but not its name.Intermediate
• Input/Output Operations Per Second (IOPS)A storage performance metric counting how many read and write operations a device or system completes each second.Intermediate
• Integrated Dell Remote Access Controller (iDRAC)Dell's BMC for PowerEdge servers, providing remote console, virtual media, firmware updates and hardware monitoring.Foundational
• Intelligent Platform Management Interface (IPMI)A legacy standard interface for out-of-band server management through the BMC, supporting sensor reads, power control and serial-over-LAN.Intermediate
• Internet Small Computer Systems Interface (iSCSI)A protocol that carries SCSI block storage commands over TCP/IP, using TCP port 3260.Intermediate
• iostatA Linux sysstat command that reports CPU and per-device I/O statistics such as IOPS, throughput, latency and utilization.Intermediate
• iSCSI InitiatorThe client side of an iSCSI connection, implemented in software or a hardware adapter, that sends SCSI commands to a target.Intermediate
• iSCSI Qualified Name (IQN)The globally unique name format identifying iSCSI initiators and targets, based on a date and reversed domain name.Intermediate
• iSCSI TargetThe storage side of an iSCSI connection that presents LUNs to authorized initiators.Intermediate
• journalctlThe command for querying logs collected by systemd-journald, filtered by unit, time, priority or boot.Intermediate
• Journaling File SystemA filesystem that records pending changes in a journal before committing them, enabling fast and consistent recovery after a crash.Foundational
• Kernel PanicA fatal error from which the Linux kernel cannot safely recover, causing the system to halt or reboot.Intermediate
• Kernel-based Virtual Machine (KVM)A Type 1 hypervisor built into the Linux kernel that turns Linux into a host for virtual machines.Intermediate
• Linear Tape-Open (LTO)An open magnetic tape standard for high-capacity, low-cost, long-term backup and archive storage.Foundational
• Linux Boot ProcessThe sequence of firmware, boot loader, kernel, initramfs and init system that brings a Linux host to an operational state.Intermediate
• Load AverageThe average number of processes running or waiting for CPU or uninterruptible I/O over 1, 5 and 15 minutes on Linux.Intermediate
• Logical Unit Number (LUN)An identifier for a logical block device presented by a storage system to hosts; commonly used to mean the volume itself.Foundational
• Logical Volume Manager (LVM)A Linux storage layer that pools physical disks into volume groups and carves flexible, resizable logical volumes from them.Intermediate
• lsblkA Linux command that lists block devices in a tree, showing disks, partitions, LVM volumes and their mount points.Foundational
• LUN MaskingAn array-side access control that makes a LUN visible only to specified host initiators.Intermediate
• Master Boot Record (MBR)A legacy partitioning scheme storing the boot loader and partition table in the first 512-byte sector of a disk.Foundational
• MirroringWriting identical copies of data to two or more drives or systems for redundancy.Foundational
• Multipath I/O (MPIO)Using multiple physical paths between a host and storage for redundancy and load balancing, managed by multipathing software.Intermediate
• N+1 RedundancyA design providing one more component than needed to carry the load, so any single unit can fail or be maintained without impact.Foundational
• Nested RAIDRAID levels combining two schemes, such as RAID 50 (striped RAID 5 sets) or RAID 60 (striped RAID 6 sets).Intermediate
• Network BondingCombining multiple Linux network interfaces into one logical interface for redundancy or increased throughput.Intermediate
• Network File System (NFS)A file-sharing protocol common in Unix and Linux environments, using TCP and UDP port 2049.Intermediate
• Network-Attached Storage (NAS)A storage device connected to a network that provides file-level access using protocols such as SMB and NFS.Foundational
• NIC TeamingCombining multiple NICs on a host into one logical interface for redundancy, load balancing or both.Intermediate
• Non-Uniform Memory Access (NUMA)A multiprocessor memory architecture in which each CPU socket has local memory that it accesses faster than another socket's memory.Advanced
• Non-Volatile Memory Express (NVMe)A storage protocol designed for flash that connects SSDs over PCIe with deep parallel queues and low latency.Foundational
• NTFSThe New Technology File System, the standard journaling filesystem for Windows with permissions, encryption, compression and quotas.Foundational
• NTFS PermissionsFile and folder access controls on NTFS volumes, such as Full Control, Modify, Read and Execute, applying both locally and over the network.Foundational
• NVMe over Fabrics (NVMe-oF)An extension of NVMe that carries NVMe commands across networks such as RDMA, Fibre Channel or TCP for low-latency shared flash storage.Advanced
• NVMe/TCPAn NVMe-oF transport that runs NVMe over standard TCP/IP Ethernet networks without requiring RDMA or lossless configuration.Advanced
• Object StorageStorage architecture that manages data as objects with metadata and unique keys in a flat namespace, accessed via HTTP APIs.Foundational
• Organizational Unit (OU)Container for AWS accounts within AWS Organizations used to group accounts and apply policies hierarchically.Intermediate
• ParityRedundant data calculated, typically with XOR, from data blocks so a lost block can be reconstructed.Foundational
• Performance MonitorA Windows tool for real-time and logged collection of performance counters for CPU, memory, disk and network.Intermediate
• Power Distribution Unit (PDU)A device that distributes electrical power to equipment in a rack, ranging from basic power strips to metered and switched intelligent units.Foundational
• Power Usage Effectiveness (PUE)A data center efficiency metric equal to total facility power divided by IT equipment power; 1.0 is ideal.Foundational
• PowerShellMicrosoft's cross-platform, object-based command shell and scripting language for automating Windows Server and cloud administration.Foundational
• Preboot Execution Environment (PXE)A standard that lets a computer boot from the network, using DHCP to find a boot server and TFTP to download a boot image.Intermediate
• Queue DepthThe number of outstanding I/O requests that can be pending to a storage device or path at one time.Advanced
• Rack UnitThe standard unit of vertical height for rack-mounted equipment, equal to 1.75 inches (44.45 mm).Foundational
• RAID 0Disk striping across two or more drives for maximum performance and capacity with no redundancy.Foundational
• RAID 1Disk mirroring, writing identical data to two drives so the array survives one drive failure.Foundational
• RAID 10A nested level that stripes data across mirrored pairs, combining RAID 1 redundancy with RAID 0 performance.Foundational
• RAID 5Striping with distributed single parity across three or more drives, tolerating one drive failure.Foundational
• RAID 6Striping with dual distributed parity across four or more drives, tolerating two simultaneous drive failures.Foundational
• RAID RebuildThe process of reconstructing a failed drive's data onto a replacement or spare from mirror copies or parity.Intermediate
• Recovery Point Objective (RPO)Maximum acceptable amount of data loss measured in time before a disruption.Foundational
• Recovery Time Objective (RTO)Maximum acceptable time to restore a service after a disruption.Foundational
• RedfishA DMTF standard RESTful API using HTTPS and JSON for modern, secure, scalable out-of-band server management.Intermediate
• Redundant Array of Independent Disks (RAID)A technique combining multiple drives into one logical unit for performance, redundancy or both, using striping, mirroring or parity.Foundational
• Redundant Power SupplyTwo or more power supply units in a server, each able to carry the load alone so one can fail without downtime.Foundational
• Registered DIMM (RDIMM)A server memory module with a register that buffers address and command signals, enabling more modules per channel.Intermediate
• Registered Memory (RDIMM)Server memory with a register that buffers command and address signals, allowing more modules per channel.Intermediate
• Remote Desktop Services (RDS)The Windows Server role set that delivers session-based desktops, virtual desktops and RemoteApp programs to users.Intermediate
• Restore TestingRegularly verifying that backups can actually be restored and meet recovery objectives.Foundational
• rsyslogA widely used Linux syslog daemon that writes log messages to files and can forward them to remote log servers.Intermediate
• sarThe System Activity Reporter, a sysstat tool that collects and reports historical CPU, memory, disk and network performance data.Intermediate
• Secure BootUEFI feature that allows only cryptographically signed bootloaders and OS components to run at startup.Intermediate
• Serial ATA (SATA)A common serial interface for hard drives and SSDs, with a 6 Gb/s maximum in SATA III, used in desktops and lower-tier servers.Foundational
• Serial Attached SCSI (SAS)A point-to-point serial interface for enterprise drives, offering dual-porting, higher reliability and compatibility with SATA drives.Foundational
• Server CoreA minimal Windows Server installation option without the desktop GUI, managed remotely or from the command line.Foundational
• Server ManagerThe built-in Windows Server console for adding roles and features and monitoring local and remote servers.Foundational
• Server Message Block (SMB)The Windows file and printer sharing protocol, running directly over TCP port 445.Foundational
• Simultaneous Multithreading (SMT)A CPU feature that lets each physical core run two hardware threads, presenting more logical processors to the OS.Intermediate
• Single Root I/O Virtualization (SR-IOV)A PCIe standard that lets one physical device present multiple virtual functions directly to VMs, bypassing the hypervisor switch.Advanced
• Software RAIDRAID implemented by the operating system rather than a dedicated controller, such as Linux mdadm or Windows Storage Spaces.Intermediate
• Software-Defined Storage (SDS)Storage in which management and data services run as software on commodity hardware, decoupled from proprietary arrays.Intermediate
• Storage Area Network (SAN)A dedicated high-speed network that gives servers block-level access to shared storage.Intermediate
• Storage LatencyThe time taken to complete a single storage I/O request, usually measured in milliseconds or microseconds.Intermediate
• Storage SnapshotA point-in-time, typically space-efficient image of a volume, created using copy-on-write or redirect-on-write.Intermediate
• Storage TieringAutomatically placing data on different classes of media, such as NVMe, SSD, HDD or cloud, based on access frequency and policy.Intermediate
• StripingSplitting data into blocks written sequentially across multiple drives so they can be accessed in parallel.Foundational
• Swap SpaceDisk space used as overflow for physical RAM, where the kernel moves inactive memory pages when memory is under pressure.Foundational
• Synthetic Full BackupA full backup assembled on the backup server from an earlier full and subsequent incrementals, without re-reading production data.Intermediate
• systemctlThe command-line tool for controlling systemd units and inspecting system state.Foundational
• systemdThe default Linux init system and service manager that runs as PID 1 and starts, stops and supervises services and other units.Foundational
• Thick ProvisioningAllocating the full storage capacity for a volume or virtual disk at creation time.Intermediate
• Thin ProvisioningAllocating storage capacity on demand as data is written rather than reserving the full size upfront.Foundational
• ThroughputThe actual rate of successful data delivery over a link or path, usually lower than the rated bandwidth.Foundational
• topAn interactive Linux utility that continuously displays processes, CPU, memory and load average.Foundational
• Type 1 HypervisorA bare-metal hypervisor that runs directly on server hardware without a general-purpose host operating system.Foundational
• Type 2 HypervisorA hosted hypervisor that runs as an application on top of a conventional operating system.Foundational
• Unified Extensible Firmware Interface (UEFI)Modern system firmware that replaces legacy BIOS, supporting GPT boot disks, Secure Boot and a pre-boot environment.Foundational
• Uninterruptible Power Supply (UPS)A device that provides immediate battery-backed power during utility outages and conditions power for connected equipment.Foundational
• Uptime Institute Tier ClassificationThe Uptime Institute's four-level data center standard (Tier I to IV) rating infrastructure redundancy, maintainability and fault tolerance.Intermediate
• Virtual CPU (vCPU)A virtual processor presented to a VM, scheduled by the hypervisor onto physical cores or threads.Intermediate
• Virtual Machine (VM)A software-defined computer with virtual hardware that runs its own operating system on top of a hypervisor.Foundational
• Virtual Machine SnapshotA point-in-time capture of a VM's disk state, and optionally memory, used for short-term rollback.Foundational
• vmstatA Linux command reporting virtual memory, process, CPU, paging and I/O statistics at intervals.Intermediate
• VMware ESXiVMware's Type 1 bare-metal hypervisor, the foundation of VMware vSphere and VMware Cloud Foundation.Foundational
• Volume Shadow Copy Service (VSS)A Windows framework that coordinates requesters, writers and providers to create consistent point-in-time shadow copies of volumes.Intermediate
• Windows Server EditionsThe licensing editions of Windows Server, chiefly Standard and Datacenter, differing in virtualization rights and advanced features.Foundational
• Windows Server Update Services (WSUS)An on-premises Windows Server role for approving and distributing Microsoft updates to managed computers.Intermediate
• World Wide Name (WWN)A 64-bit globally unique identifier assigned to Fibre Channel devices, with node (WWNN) and port (WWPN) variants.Intermediate
• Write-Back CacheA caching mode where writes are acknowledged once stored in cache, then flushed to disk later, improving write performance.Intermediate
• XFSA high-performance 64-bit journaling filesystem and the default filesystem in Red Hat Enterprise Linux.Intermediate
• ZFSA combined filesystem and volume manager offering pooled storage, copy-on-write, end-to-end checksums, snapshots and software RAID-Z.Advanced