XFS is a high-performance 64-bit journaling file system created by Silicon Graphics, Inc (SGI) in 1993. It was the default file system in SGI's IRIX operating system starting with its version 5.3. XFS was ported to the Linux kernel in 2001; as of June 2014, XFS is supported by most Linux distributions; Red Hat Enterprise Linux uses it as its default file system.
RAID is a data storage virtualization technology that combines multiple physical data storage components into one or more logical units for the purposes of data redundancy, performance improvement, or both. This is in contrast to the previous concept of highly reliable mainframe disk drives known as single large expensive disk (SLED).
A RAM drive is a block of random-access memory that a computer's software is treating as if the memory were a disk drive. RAM drives provide high-performance temporary storage for demanding tasks and protect non-volatile storage devices from wearing down, since RAM is not prone to wear from writing, unlike non-volatile flash memory.
Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU).
A live CD is a complete bootable computer installation including operating system which runs directly from a CD-ROM or similar storage device into a computer's memory, rather than loading from a hard disk drive. A live CD allows users to run an operating system for any purpose without installing it or making any changes to the computer's configuration. Live CDs can run on a computer without secondary storage, such as a hard disk drive, or with a corrupted hard disk drive or file system, allowing data recovery.
In computer storage, logical volume management or LVM provides a method of allocating space on mass-storage devices that is more flexible than conventional partitioning schemes to store volumes. In particular, a volume manager can concatenate, stripe together or otherwise combine partitions into larger virtual partitions that administrators can re-size or move, potentially without interrupting system use.
External sorting is a class of sorting algorithms that can handle massive amounts of data. External sorting is required when the data being sorted do not fit into the main memory of a computing device and instead they must reside in the slower external memory, usually a disk drive. Thus, external sorting algorithms are external memory algorithms and thus applicable in the external memory model of computation.
In computing, a benchmark is the act of running a computer program, a set of programs, or other operations, in order to assess the relative performance of an object, normally by running a number of standard tests and trials against it.
In the fields of digital electronics and computer hardware, multi-channel memory architecture is a technology that increases the data transfer rate between the DRAM memory and the memory controller by adding more channels of communication between them. Theoretically, this multiplies the data rate by exactly the number of channels present. Dual-channel memory employs two channels. The technique goes back as far as the 1960s having been used in IBM System/360 Model 91 and in CDC 6600.
A hybrid drive is a logical or physical computer storage device that combines a faster storage medium such as solid-state drive (SSD) with a higher-capacity hard disk drive (HDD). The intent is adding some of the speed of SSDs to the cost-effective storage capacity of traditional HDDs. The purpose of the SSD in a hybrid drive is to act as a cache for the data stored on the HDD, improving the overall performance by keeping copies of the most frequently used data on the faster SSD drive.
sync is a standard system call in the Unix operating system, which commits all data from the kernel filesystem buffers to non-volatile storage, i.e., data which has been scheduled for writing via low-level I/O system calls. Higher-level I/O layers such as stdio may maintain separate buffers of their own.
Vinum is a logical volume manager, also called software RAID, allowing implementations of the RAID-0, RAID-1 and RAID-5 models, both individually and in combination. The original Vinum was part of the base distribution of the FreeBSD operating system since 3.0, and also NetBSD between 2003-10-10 and 2006-02-25, as well as descendants of FreeBSD, including DragonFly BSD; in more recent versions of FreeBSD, it has been replaced with gvinum, which was first introduced around FreeBSD 6. Vinum source code is maintained in the FreeBSD and DragonFly source trees. Vinum supports RAID levels 0, 1, 5, and JBOD. Vinum was inspired by Veritas Volume Manager.
A solid-state drive (SSD) is a type of solid-state storage device that uses integrated circuits to store data persistently. It is sometimes called semiconductor storage device, solid-state device, or solid-state disk.
Kernel-based Virtual Machine (KVM) is a free and open-source virtualization module in the Linux kernel that allows the kernel to function as a hypervisor. It was merged into the mainline Linux kernel in version 2.6.20, which was released on February 5, 2007. KVM requires a processor with hardware virtualization extensions, such as Intel VT or AMD-V. KVM has also been ported to other operating systems such as FreeBSD and illumos in the form of loadable kernel modules.
GEOM is the main storage framework for the FreeBSD operating system. It is available in FreeBSD 5.0 and later releases, and provides a standardized way to access storage layers. GEOM is modular and allows for geom modules to connect to the framework. For example, the geom_mirror module provides RAID1 or mirroring functionality to the system. A number of modules are provided as part of FreeBSD and others have been developed independently and are distributed via (e.g.) GitHub.
A trim command allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered to be "in use" and therefore can be erased internally.
NVM Express (NVMe) or Non-Volatile Memory Host Controller Interface Specification (NVMHCIS) is an open, logical-device interface specification for accessing a computer's non-volatile storage media usually attached via the PCI Express bus. The initial NVM stands for non-volatile memory, which is often NAND flash memory that comes in several physical form factors, including solid-state drives (SSDs), PCIe add-in cards, and M.2 cards, the successor to mSATA cards. NVM Express, as a logical-device interface, has been designed to capitalize on the low latency and internal parallelism of solid-state storage devices.
OpenZFS is an open-source implementation of the ZFS file system and volume manager initially developed by Sun Microsystems for the Solaris operating system, and is now maintained by the OpenZFS Project. Similar to the original ZFS, the implementation supports features like data compression, data deduplication, copy-on-write clones, snapshots, RAID-Z, and virtual devices that can create filesystems that span multiple disks.
bcache is a cache mechanism in the Linux kernel's block layer, which is used for accessing secondary storage devices. It allows one or more fast storage devices, such as flash-based solid-state drives (SSDs), to act as a cache for one or more slower storage devices, such as hard disk drives (HDDs); this effectively creates hybrid volumes and provides performance improvements.
ZFS is a file system with volume management capabilities. It began as part of the Sun Microsystems Solaris operating system in 2001. Large parts of Solaris, including ZFS, were published under an open source license as OpenSolaris for around 5 years from 2005 before being placed under a closed source license when Oracle Corporation acquired Sun in 2009–2010. During 2005 to 2010, the open source version of ZFS was ported to Linux, Mac OS X and FreeBSD. In 2010, the illumos project forked a recent version of OpenSolaris, including ZFS, to continue its development as an open source project. In 2013, OpenZFS was founded to coordinate the development of open source ZFS. OpenZFS maintains and manages the core ZFS code, while organizations using ZFS maintain the specific code and validation processes required for ZFS to integrate within their systems. OpenZFS is widely used in Unix-like systems.