|
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 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 FlashCopy commands were issued sequentially and the ESS required a brief moment to establish the new pointers. Because of this minute processing delay, the data residing on two volumes that were FlashCopied are not exactly time consistent. Version 2 Flash ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Mirror
Global Mirror is an IBM technology that provides data replication over extended distances between two sites for business continuity and disaster recovery. If adequate bandwidth exists, Global Mirror provides a recovery point objective (RPO) of as low as 3–5 seconds between the two sites at extended distances with no performance impact on the application at the primary site. It replicates the data asynchronously and also forms a consistency group at a regular interval allowing a clean recovery of the application. The two sites can be on separate continents or simply on different utility grids. IBM also provides a synchronous data replication called Metro Mirror, which is designed to support replication at "Metropolitan" distances of (normally) less than 300 km. Global Mirror is based on IBM Copy Services functions: Global Copy and FlashCopy. Global mirror periodically pauses updates of the primary volumes and swaps change recording bitmaps. It then uses the previous b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snapshot (computer Storage)
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 the Hitachi Information Systems & Telecommunications Division. In 2017 its operations were merged with Pentaho and Hitachi Insight Group to form Hitachi Vantara. In 2010, Hitachi Data Systems sold through direct and indirect channels in more than 170 countries and regions. Its customers included over half of the Fortune 100 companies at the time. History Origins as Itel Itel was an equipment leasing company founded in 1967 by Peter Redfield and Gary Friedman, initially focusing on leasing IBM mainframes. Through creative financial arrangements and investments, Itel was able to lease IBM mainframes to customers at costs below what customers would have paid IBM, making them second to IBM itself in revenues. A joint venture between Nationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System Z
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers. In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest model, the IBM z16, as well as the z15, the z14, and the z13 (released under the IBM z Systems/IBM System z names), the IBM zEnterprise models (in common use the zEC12 and z196), the IBM System z10 models (in common use the z10 EC), the IBM System z9 models (in common use the z9EC) and ''IBM eServer zSeries'' models (in common use refers only to the z900 and z990 generations of mainframe). Architecture The ''zSeries,'' ''zEnterprise,'' ''System z'' and ''IBM Z'' families were named for their availability – ''z'' stands for High availability, zero downtime. The systems are built with spare components capable of hot Failover, failovers to ensure continuous operations. The IBM Z family maintains full backward compatibility. In effect, curren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
