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IBM SAN Volume Controller
The IBM SAN Volume Controller (SVC) is a block storage virtualization appliance that belongs to the IBM System Storage product family. SVC implements an indirection, or "virtualization", layer in a Fibre Channel storage area network (SAN). Architecture The IBM 2145 SAN Volume Controller (SVC) is an inline virtualization or "gateway" device. It logically sits between hosts and storage arrays, presenting itself to hosts as the storage provider (target) and presenting itself to storage arrays as one big host. SVC is physically attached to one or several SAN fabrics. The virtualization approach allows for non-disruptive replacements of any part in the storage infrastructure, including the SVC devices themselves. It also aims at simplifying compatibility requirements in strongly heterogeneous server and storage landscapes. All advanced functions are therefore implemented in the virtualization layer, which allows switching storage array vendors without impact. Finally, spreading an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM FlashSystem
IBM FlashSystem is an IBM Storage enterprise system that stores data on flash memory. Unlike storage systems that use standard solid-state drives, IBM FlashSystem products incorporate custom hardware based on technology from the 2012 IBM acquisition of Texas Memory Systems. According to Gartner, IBM was the number one all-flash storage array vendor in 2014 selling over 2,100 FlashSystems totaling 62 petabytes (PB) of capacity. The IBM FlashSystem commanded 33% of the total all-flash capacity sold by all vendors for the year. As of February 12, 2020 the FlashSystem brand has replaced both the Storwize and XIV brands in IBM. History Origin The IBM FlashSystem architecture was originally developed by Texas Memory Systems (TMS) as their RamSan product line. TMS was a small private company founded in 1978 and based in Houston, Texas that supplied solid-state drive products to the market longer than any other company. The TMS RamSan line of enterprise solid state storage p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storage Virtualization
In computer science, storage virtualization is "the process of presenting a logical view of the physical storage resources to" a host computer system, "treating all storage media (hard disk, optical disk, tape, etc.) in the enterprise as a single pool of storage." A "storage system" is also known as a storage array, disk array, or ''filer''. Storage systems typically use special hardware and software along with disk drives in order to provide very fast and reliable storage for computing and data processing. Storage systems are complex, and may be thought of as a special purpose computer designed to provide storage capacity along with advanced data protection features. Disk drives are only one element within a storage system, along with hardware and special purpose embedded software within the system. Storage systems can provide either block accessed storage, or file accessed storage. Block access is typically delivered over Fibre Channel, iSCSI, SAS, FICON or other protoco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VDisk
A logical disk, logical volume or virtual disk (VD or vdisk for short) is a virtual device that provides an area of usable storage capacity on one or more physical disk drive(s) in a computer system. The disk is described as ''logical'' or ''virtual'' because it does not actually exist as a single physical entity in its own right. The goal of the logical disk is to provide computer software with what seems a contiguous storage area, sparing them the burden of dealing with the intricacies of storing files on multiple physical units. Most modern operating systems provide some form of logical volume management. Levels Logical disks can be defined at various levels in the storage infrastructure. Operating system An operating system may define ''volumes'' or ''logical disks'' and assign each to one physical disk, more than one physical disk or part of the storage area of a physical disk. For example, Windows NT can create several partitions on a hard disk drive, each of which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copy-on-write
Copy-on-write (COW), sometimes referred to as implicit sharing or shadowing, is a resource-management technique used in computer programming to efficiently implement a "duplicate" or "copy" operation on modifiable resources. If a resource is duplicated but not modified, it is not necessary to create a new resource; the resource can be shared between the copy and the original. Modifications must still create a copy, hence the technique: the copy operation is deferred until the first write. By sharing resources in this way, it is possible to significantly reduce the resource consumption of unmodified copies, while adding a small overhead to resource-modifying operations. In virtual memory management Copy-on-write finds its main use in sharing the virtual memory of operating system processes, in the implementation of the fork system call. Typically, the process does not modify any memory and immediately executes a new process, replacing the address space entirely. Thus, it would be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Snapshot
In computer systems, a snapshot is the state of a system at a particular point in time. The term was coined as an analogy to that in photography. It can refer to an actual copy of the state of a system or to a capability provided by certain systems. Rationale A full backup of a large data set may take a long time to complete. On multi-tasking or multi-user systems, there may be writes to that data while it is being backed up. This prevents the backup from being atomic and introduces a version skew that may result in data corruption. For example, if a user moves a file into a directory that has already been backed up, then that file would be completely missing on the backup media, since the backup operation had already taken place before the addition of the file. Version skew may also cause corruption with files which change their size or contents underfoot while being read. One approach to safely backing up live data is to temporarily disable write access to data during ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FlashCopy
FlashCopy is an IBM feature supported on various IBM storage devices that made it possible to create, nearly instantaneously, point-in-time snapshot copies of entire logical volumes or data sets. The Hitachi Data Systems Hitachi Data Systems (HDS) was a provider of modular mid-range and high-end computer data storage systems, software and services. Its operations are now a part of Hitachi Vantara. It was a wholly owned subsidiary of Hitachi Ltd. and part of ... implementation providing similar function was branded as ShadowImage. Using either implementation, the copies are immediately available for both read and write access. Implementations Version 1 The first implementation of FlashCopy, Version 1 allowed entire volumes to be instantaneously “copied” to another volume by using the facilities of the newer Enterprise Storage Subsystems (ESS). Version 1 of FlashCopy had limitations however. Although the copy or “flash” of a volume occurred instantaneously, the Fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lempel–Ziv–Welch
Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempel and Ziv in 1978. The algorithm is simple to implement and has the potential for very high throughput in hardware implementations. It is the algorithm of the widely used Unix file compression utility compress and is used in the GIF image format. Algorithm The scenario described by Welch's 1984 paper encodes sequences of 8-bit data as fixed-length 12-bit codes. The codes from 0 to 255 represent 1-character sequences consisting of the corresponding 8-bit character, and the codes 256 through 4095 are created in a dictionary for sequences encountered in the data as it is encoded. At each stage in compression, input bytes are gathered into a sequence until the next character would make a sequence with no code yet in the dictionary. The c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Locality
In computer science, locality of reference, also known as the principle of locality, is the tendency of a processor to access the same set of memory locations repetitively over a short period of time. There are two basic types of reference locality temporal and spatial locality. Temporal locality refers to the reuse of specific data and/or resources within a relatively small time duration. Spatial locality (also termed ''data locality''"NIST Big Data Interoperability Framework: Volume 1"urn:doi:10.6028/NIST.SP.1500-1r2) refers to the use of data elements within relatively close storage locations. Sequential locality, a special case of spatial locality, occurs when data elements are arranged and accessed linearly, such as traversing the elements in a one-dimensional Array data structure, array. Locality is a type of predictability, predictable behavior that occurs in computer systems. Systems that exhibit strong ''locality of reference'' are great candidates for performance optimiza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VMotion
VMware, Inc. is an American cloud computing and virtualization technology company with headquarters in Palo Alto, California. VMware was the first commercially successful company to virtualize the x86 architecture. VMware's desktop software runs on Microsoft Windows, Linux, and macOS. VMware ESXi, its enterprise software hypervisor, is an operating system that runs on server hardware. In May 2022, Broadcom Inc. announced an agreement to acquire VMware in a cash-and-stock transaction valued at $61 billion. History Early history In 1998, VMware was founded by Diane Greene, Mendel Rosenblum, Scott Devine, Ellen Wang and Edouard Bugnion. Greene and Rosenblum were both graduate students at the University of California, Berkeley. Edouard Bugnion remained the chief architect and CTO of VMware until 2005, and went on to found Nuova Systems (now part of Cisco). For the first year, VMware operated in stealth mode, with roughly 20 employees by the end of 1998. The company w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Live Partition Mobility
Live Partition Mobility is a chargeable Live migration feature of IBM POWER6, POWER7, POWER8 and POWER9 servers, available since 2007, that allows a running LPAR to be relocated from one system to another. In concept, it is similar to VMware VMotion. Live Partition Mobility, a component of the PowerVM PowerVM, formerly known as Advanced Power Virtualization (APV), is a chargeable feature of IBM POWER5, POWER6, POWER7, POWER8, POWER9 and Power10 servers and is required for support of micro-partitions and other advanced features. Support is pr ... Enterprise Edition hardware feature, provides the ability to move AIX, IBM i, and Linux logical partitions from one system to another. The mobility process transfers the system environment that includes the processor state, memory, attached virtual devices, and connected users. The source and target systems must have access to the same network and SANs but need not be of the same type, the only requirement is they use POWER6, POWER ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IOPS
Input/output operations per second (IOPS, pronounced ''eye-ops'') is an input/output performance measurement used to characterize computer storage devices like hard disk drives (HDD), solid state drives (SSD), and storage area networks (SAN). Like benchmarks, IOPS numbers published by storage device manufacturers do not directly relate to real-world application performance. Background To meaningfully describe the performance characteristics of any storage device, it is necessary to specify a minimum of three metrics simultaneously: IOPS, response time, and (application) workload. Absent simultaneous specifications of response-time and workload, IOPS are essentially meaningless. In isolation, IOPS can be considered analogous to "revolutions per minute" of an automobile engine i.e. an engine capable of spinning at 10,000 RPMs with its transmission in neutral does not convey anything of value, however an engine capable of developing specified torque and horsepower at a given number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storage Performance Council
Storage may refer to: Goods Containers * Dry cask storage, for storing high-level radioactive waste * Food storage * Intermodal container, cargo shipping * Storage tank Facilities * Garage (residential), a storage space normally used to store cars * Mail storage, storage by mail or delivery service * Self storage, a public storage facility * Warehouse, a commercial building for storage of goods Technology * Cloud storage *Computer data storage, a means to retain digital data * Data storage, general recording and retention of information * Energy storage *Specific storage, of groundwater in an aquifer Arts and entertainment * ''Storage'' (film), a 2009 Australian horror film * ''The Storage'', a 2011 Finnish film * ''Storage'' (album), a 1988 album by Merzbow * '' Storage Wars'', a reality television show * "Storage Wars", an episode of ''One Day at a Time'' (2017 TV series) Other * Storage (memory), a psychological and physiological process See also * * * Container ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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