Difference between Data Redundancy and Backup - Essay Example

Backup Media/Redundancy/Network/Internet Number: Lecturer: Backup Media/Redundancy/Network/Internet Back up storage is the creation of a copy of resident data, programs and processes and placed in another location for safety in-case of unprecedented loss. The common types of back up include full backup, incremental backup, differential back up, local back up, remote backup, offsite backup, mirror backup, FTP backup and cloud backup. These backup types eventually require different backup media types to be used (IBM , 2014). An elaboration of the common forms of backup media is provided below: 1. Optical DVD media (DVD recordable/Rewriteable and dual layer formats) The optical DVD is used to store backup by writing the files into a blank DVD and stored somewhere else. The media provides up to a maximum of 4.97 GB of storage space to be used. The method is deemed more useful but data will be transferred to another media due to its limited storage space. It can only backup small amount of data and information (Microsoft Inc., 2014). It is most suitable for backing up music, photos, and other data from the computer’s memory. Additionally it is easy and fact to retrieve data and information backed up in this media. Advantages; It has a relatively high capacity to provide adequate backup for music and video files, pictures and other unused data from the computer memory.It is easy to retrieve the backup from the media. It is convenient for backup of files of relatively smaller capacity below 4.7GB (Microsoft Inc., 2014).This media of backup is not easily affected by computer failure or viruses as is the case with other storage media. It is cheap to purchase and maintain (Microsoft Inc., 2014). Disadvantages; Relatively small capacity for large files that need to be backed up thus requiring several Disks to successfully backup files from the computer memory. It requires maximum care to avoid scratches as a single scratch destroys the entire data in the disk. It is also a reliable form of backup media if properly stored and protected from direct sunlight, water, dust and scratches. 2. Second Hard disk Mounted Internally. A second hard disk mounted internally offers ideal backup for data that is frequently needed in case of loss of data from the resident hard disk. It is recommended as the best form of backup media due to the capacity and reliability of the media (IBM , 2014). Advantages This back up media offers fast and easy access since it is mounted internally hence the access time is short. It also has high data storage capacity. It has the capacity to back up the entire computer system in one disk. It is also easy to operate and it is convenient. It has a long term reliability if taken care of (IBM , 2014). Disadvantages The backup media is relatively expensive to purchase and additionally requires proper maintenance. It cannot withstand extreme conditions and exposure to conditions such as water, dust, sunlight and magnetic materials will damage data. The media is also affected by computer failure. When there is a computer failure, it may affect the device. It is exposed to viruses and other malicious programs in the computer (IBM , 2014). 3. A second Hard disk mounted externally This is an external Hard disk that is always mounted externally to the computer. It provides additional storage and backup. The media provides large storage capacity that can be used to backup up to three computers. It has varied storage capacity ranging from 250 GB to 1 Terabyte (Susan, 2013). Advantages External hard disks are easy and convenient to use. It is a simple plug and play device. It is also easy to access the data backup once the device is mounted on the machine. Additionally, it offers high storage capacity that can back up more than one machine. The data stored in an external hard disk is protected from computer failure since the data is stored away from the computer. The media is reliable is well stored away from extreme conditions that could damage the device. Some external hard disks are robustly designed to with stand extreme conditions including shock, dust, water and light (Susan, 2013). Disadvantages; The device is expensive to purchase as compared to other devices such as optical disks. They can also be easily infected by viruses and malicious codes that could result in loss of backed up data and information (Susan, 2013). 4. Solid state Flash Memory Solid state storage (SSS) is computer storage that is made from silicon microchips and stores data electronically and not magnetically as is the norm in other storage technologies (Susan, 2013). The media does not contain any mechanical parts thus allowing fast data transfer, additionally; it offers a more predictable lifespan for the device. Most of the devices such as flash disks, memory cards among others are cheap to purchase and maintain. They are easy to operate and are much convenient due to their portability. These devices can be used to backup any type of data and information and is not affected by computer failure (Susan, 2013). However they are always prone to virus attack and malicious codes. 5. Cloud storage This is a type of backup where information is uploaded to a server that is located in a different location. Examples include drop box, Google drive and Icloud where data and information can be stored online (Microsoft Inc., 2014). It provides a more efficient form of backup that is accessible from any location. It is cheap and offers considerable storage capacity. It is also not affected by any extreme conditions since one doesn’t require any hardware. Additionally, the backup media is reliable and convenient since one does not have to carry data around. Data stored in cloud storage is safe from damage (Microsoft Inc., 2014). However, once data is uploaded online, there is no guarantee that it is confidential and cannot be accessed by anyone else hence privacy of data is jeopardised. Accessibility to the data depends on the speed of the internet connection; it may be slow to access if one is using a slow internet connection (Microsoft Inc., 2014). Generally the form of data backup is reliable and can be used to back up pictures, files, music, videos and other data that is not too confidential (Microsoft Inc., 2014). Difference between data redundancy and backup Data redundancy and data backup are two popular forms of data protection. However, the two techniques have different meanings and operate differently (Dong, 2013). Data redundancy is basically a digital data storage that involves the use more than one internal storage drives to store the same information or data. This entails storage of the same information several times in several different locations. On the other hand, data backup is creation of a copy of data and storing it in a separate location solely for purpose of having a second copy of the original source in case the original source is lost or damaged. Therefore redundancy is not a form of backup but a safety measure against failure (Dong, 2013). Data redundancy is useful in a database setup where data availability is fundamental for the functionality of the database. Data redundancy ensures the data is replicated in several disks which can easily be accessed in case one disk fails. It is therefore a fast, reliable and readily available way of data protection. It is also useful in real time processing where data is needed in real time. Therefore, redundancy ensures the data is available even when there is failure in one or two storage disks. Additionally, when the disk fails the system only informs the user so that one can back up the important data and repair the disk without affecting data processing (Dong, 2013). There are some disaster situations in which data redundancy cannot recover from. These situations are basically associated with the mode of redundancy that is employed (Petterson, Garth, & Randy, 2012). Redundancy can fail when only a copy of the data is replicated as is the case is RAID 1. The only copy can be damaged hence recovery becomes difficult. Additionally, when redundant storage uses RAID 5 which allows two copies of the original source the recovery can still fail in case there is loss or damage of multiple components (Petterson, Garth, & Randy, 2012). RAID 0 is also referred to as stripping. Essentially RAID 0 is not a type of redundant storage; disks are stacked together in an array to make a large disk. In this scenario, when one of the disk fails the entire array fails (Hai & Kai, 1998). This technique is rarely used for data that is important due to this shortfall. However, access to data with striping is fast because each disk reads part of the file at the same time. It is mainly used for swap space on Linux or UNIX operating systems. In RAID 1 two disks are placed together and data replicated on each other, the two disks essentially mirror one another. This concept offers more chances of data recovery since the data is mirrored on another disk hence when one disk fails the other continues to provide data for processing (Hai & Kai, 1998). Parity concept is utilized in RAID 5. Here a minimum of three disks is used to carry out the redundancy storage. RAID 5 utilizes the fact that failed disks are self-identifying thus achieving fault tolerance using a parity code. The parity access bottlenecks are avoided by the rotation of the parity blocks through the array and not concentrated on a single disk. This is always combined with stripping which consequently offers improved performance and reliability for a wide range of applications (Hai & Kai, 1998). Network and internet Data can be corrupted during creation, storage or transmission from one computer system to another in a network (Charles, 2001). Data is often corrupted due to viruses that are resident in the computer systems in the network. For instance, a word file can be corrupted and becomes inaccessible in other computer systems in the network. Therefore, when the user tries to open the file an error message appears. Data corruption is mainly caused by power related problems, poor handling of computer systems such as improper shut downs, hardware problems or failures, bad sectors or bad RAM among others (Charles, 2001). The errors can be detected by using mechanisms such as checksums and corrected using error correction codes. The hard disk drives detect and correct errors using the ECC or CRC codes that are stored in the disk for each sector. The disk can additionally perform the correction by mapping the failed or corrupt sectors to a spare disk without the involvement of the operating system (Charles, 2001). The transport layer of the TCP/IP protocol suite comprises of two major protocols; Transmission control protocol and the user datagram protocol. TCP protocol handles transmission of data from the application layer of the TCP/IP protocol. The protocol organizes the data packets into segments in a sequential order then sent to the destination. The data packets can be sent sequentially or in any other possible order. Once files are received the recipient sends an acknowledgement to the sender and if it is not received an ICMP message is sent to have the specified data packet resent. The protocol guarantees delivery of all packets to the destination (Buse, 2013). The protocol additionally manages flow by setting up a window size which is the amount of data that can be transmitted. User datagram Protocol (UDP) on the hand operates just like the TCP but without a guarantee of delivery of data packets. It also has lower overhead because it doesn’t require acknowledgements of packets received. UDP is similar to TCP, but without the guarantee of delivery. UDP has a lower overhead by not requiring acknowledgments of packet received it is also much faster compared to the TCP protocol (Buse, 2013). UDP is not suitable for multicasting data due to the fact that the lost packets of data are skipped and cannot be resent due to the lack of acknowledgement. It can be used for simple queries such as DNS queries because they are faster than TCP (Buse, 2013). Peer-to-peer computer system is a decentralized environment where computers connect directly to one another on the same level. All the components of the network have equal rights and either can initiate communication with the other. It is deemed as a relevant model for end systems only. This system exhibits a many to many relationship where several users download and access information from many sources (Dmitri, 2013). Due to its nature, there is no need for dedicated applications and database servers in the peer-to-peer model. Additionally, there is improved scalability and reliability because there are limited chances of complete failure. The lack of central control relieves other workstations from central dependency (Dmitri, 2013). However, the system lacks centralized control and therefore there is poor security in the system. This makes it prone to attacks such as hacking. Computers with shared resources in this system tend to become slow and sluggish (Dmitri, 2013). Client-server systems are centralized distributed systems that partitions workloads or tasks between the providers of services called servers and the requesters of these data and services called clients. All users, objects and resources are administered from a centralized location. In this system, clients have an active role and they can initiate communication with the server when need be. On the other hand the servers have passive roles and can only respond to requests from the clients. The system exhibits a one to many relationships where one server can serve several clients (Dmitri, 2013). This model is more secure and is less prone to virus attacks and unauthorised access. It is also much easier to keep software and other shared resources up to date. In this model there are fewer points of failure and has low TCO (Total Cost of Ownership) (Dmitri, 2013). The system however, has a central point of failure at the server. Once the server fails, the whole system fails. This system also tends to be proprietary (Dmitri, 2013). Distributed computer systems A distributed computer system is a collection of autonomous computers that are linked together by a network using software and produces an integrated computing facility (Dmitri, 2013). The distributed system is centralized and the server controls operations in the system. There could be a series of servers depending on the scope of the network. Computers in a particular network domain are served by one server which is connected to another server that controls another network. This system is commonly used by organizations that have branches and departments spread in different locations (Dmitri, 2013). Distributed systems have single authority; it also has improved security and reduces cases of unauthorised access by use of firewalls and access restrictions and authorization. It has high chances of scalability, increased reliability and fault tolerance (Charles, 2001). Due to the centralized control, the server is the source point of failure in the system. References Buse, W. (2013, October 21). TCP/IP Transport layer Protocols. Retrieved May 6, 2014, from Linux.org: http://www.linux.org/threads/tcp-ip-transport-layer-protocols.4797/ Charles, M. K. (2001, April 17). Error detection and correction. Retrieved May 6, 2014, from Pcguide.com: http://pcguide.com/ref/hdd/geom/errorRead-c.html Dmitri, M. (2013, September 4). Client-server and peer-to-peer Models: Basic concepts. Retrieved May 6, 2014, from Cs.tut: http://www.cs.tut.fi/kurssit/ELT-53206/lecture01.pdf Dong, N. (2013, March 29). Digital Storage Basics Part 3:Backup Vs Redundancy. Retrieved May 6, 2014, from cnet.com: www.cnet.com/how-to/digital-storage-basics-part-3-backup-vs-redundancy/ Hai, J., & Kai, H. (1998). Stripped mirroring RAID architecture. Journal Of Systems Architecture, 543-544. IBM . (2014). Backup media. Retrieved May 5, 2014, from IBM.com: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.baseadmn/doc/baseadmndita/backmed.htm Microsoft Inc. (2014). Methods for backing up your files. Retrieved May 6, 2014, from Windows Microsoft: http://windows.microsoft.com/en-us/windows-vista/methods-for-backing-up-your-files Petterson, D., Garth, G., & Randy, K. (2012). A Case of Redundant Arrays of Inexpensive Disks. Retrieved May 6, 2014, from Cs.cmu: http://www.cs.cmu.edu/~garth/RAIDpaper/Patterson88.pdf Susan, W. (2013). Data Back up: Which Data Back Up is the Best. Retrieved May 5, 2014, from About.com: http://sbinfocanada.about.com/cs/management/a/databackup_2.htm Read More