Prior to going through the benefits associated with virtual storage in systems, it is imperative to define it. Virtual storage is a system mechanism in which the size of the memory is effectively augmented by automatically transferring sections of a program from a large capacity backing store, such as a disk, into the smaller core memory as they are required. It can also be defined as the memory created by using the hard disk to simulate additional random-access memory (RAM).
It is important to note that the main rationale in virtual storage is the development of a virtual device description that supports virtual storage. The functionality offered by virtual storage makes it an important technology in increasing the efficiency that can be attained by system i architecture based systems. This is because of a number of reasons that have been highlighted as the benefits gained by virtual storage.
Benefits associated with virtual storage include: elimination of media error and user intervention; simplification of software and data distribution; increase in system availability; allowance for the creation of DVD and CD tape; increase in the levels of security that can be attained by object signing and digital signature; and simplification of the process of creating copies with the aid of catalog shadowing. In essence the benefits can be looked at from different perspectives namely increase in system security, availability and usability.
Elimination of media errors ensure availability of the system which is an important aspect in ensuring that system resources are used optimally. Use of digital signatures and object signings that is enhanced by virtual storage improves the security of files stored in a system. Increase in system availability, simplification of copying and software and data distribution are all important in ensuring resources and processor availability thus usability. The performance of a computer system is highly dependent on the utilities that a user is provided and access to processor and system resources. Virtual storage under system i architecture addresses these areas which makes it one of its important technologies.
Monday, September 20, 2010
IBM System: A Critical Review of i Disk Storage Capabilities
The internal storage system employed by system i architecture in IBM systems brings out the correct meaning of data storage in computing. Storage under system i architecture involves ensuring that data is protected; ensuring ease of use of data; minimizing the cost of storing data and minimizing maintenance requirements. Moreover, the multiple options that are offered by the system i architecture for integrated disk and tape drives allow for maximum flexibility in data storage.
The numerous hardware functions provided by the system i architecture, allow efficient use of disk space and data protection. Device parity protection is an example of such functions which protects against data loss in case of disk failure or disk damage. The function works by calculating and saving parity value for each bit of data that is entered into a disk. In addition to ensuring that data is not lost, device parity protection allows for high availability of system resources by ensuring that operations are continued despite failure of a disk. Other tools that seek to address disk failure include RAID-5 which comes in handy in case of failure of a single disk unit and RAID-6 which ensures availability in case of failure of two disk units.
Mirroring and cross site mirroring are advanced functions that increase availability of servers in case of disk-related hardware component failure. Mirroring functions are i5/OS operating system functions that allow for duplicating of disk related hardware for instance the bus and disk devices for use in case of failure. Cross site mirroring on the other hand allows for keeping identical copies of data which extends the functionality of device clustered resource groups.
Disk space management is made easy by integrated hardware disk compression functionality. Every time data is written or read from a disk the disk controllers dynamically compress or ‘uncompress’ data. It is important to note that the processes do not affect the use of the CPU. Compression allows effective use of disk space by reducing the volume of data and metadata.
The numerous hardware functions provided by the system i architecture, allow efficient use of disk space and data protection. Device parity protection is an example of such functions which protects against data loss in case of disk failure or disk damage. The function works by calculating and saving parity value for each bit of data that is entered into a disk. In addition to ensuring that data is not lost, device parity protection allows for high availability of system resources by ensuring that operations are continued despite failure of a disk. Other tools that seek to address disk failure include RAID-5 which comes in handy in case of failure of a single disk unit and RAID-6 which ensures availability in case of failure of two disk units.
Mirroring and cross site mirroring are advanced functions that increase availability of servers in case of disk-related hardware component failure. Mirroring functions are i5/OS operating system functions that allow for duplicating of disk related hardware for instance the bus and disk devices for use in case of failure. Cross site mirroring on the other hand allows for keeping identical copies of data which extends the functionality of device clustered resource groups.
Disk space management is made easy by integrated hardware disk compression functionality. Every time data is written or read from a disk the disk controllers dynamically compress or ‘uncompress’ data. It is important to note that the processes do not affect the use of the CPU. Compression allows effective use of disk space by reducing the volume of data and metadata.
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