What is scalability ?

What is scalability ? ABSTRACT: The rapid development of large clusters built with commodity hardware has highlighted scalability issues with deploying and effectively running system software in large clusters. The concept of scalability applies to business and technology. In this the base concept is consistent i.e., the ability for a business or a technology to accept increased volume without impacting the revenue variable costs. For example in some cases the variable cost will increase and reduce the revenue variable costs. INTRODUCTION TO SCALABILTY: It is a performance measure for the execution of the software that refers to its ability to accommodate expanding traffic measures like number of users, activity of each user and so on. In telecommunications and software engineering, scalability is a desirable property of system, network, process which indicates its ability to either handle growing amounts of work in a graceful manner or to be readily enlarged. For example, it can refer to the capacity of the system to increase total throughput under an increased load when resources are added. Scalability is generally difficult to define and in some case we define the specific requirements for scalability on some important dimensions. It is a highly significant issue in database, routers and networking. Scalable system is the system whose performance improves after adding hardware proportional to the capacity added is called scalable system. An algorithm, design, networking protocol, program or other system is sad to scale if it is suitably efficient and practical when applied to large situations. If the design fails when the quantity increases then it does not scale. IMPORTANCE OF SOFTWARE SCALABILITY: Software scalability analysis is an important issue for most businesses. It is essential that as the customer base increases, the system has to deal with significantly increased loads, the system is designed to handle the increased traffic so that the users do not encounter unacceptable system performance. Scalability is an important goal for many software development projects and software installations because without scalability success might be hampered by poor performance as observed by end users. MEASUREMENT FO SOFTWARE SCALABILITY: The various dimensions by which the scalability can be measured are: Load scalability: it is the ability of a distributed system to easily expand and contract its resource pool to accommodate heavier or lighter loads. Geographic scalability: It is the ability to maintain performance, usefulness, or usability regardless of the expansion from concentration in the local area to a more geographic pattern. Administrative scalability: The ability for an increasing number of organizations to easily share a single distributed system. Functional scalability: The ability to enhance the system by adding new functionality at minimal effort. DESIGN FOR SCALABILITY: It is often advised to focus system design on hardware scalability rather than on capacity. It is typically cheaper to add a new node to a system in order to achieve improved performance than to partake in performance tuning to improve the capacity that each node can handle. But this approach can have diminishing returns (as discussed in performance engineering). For example: suppose a portion of a program can be sped up by 70% if parallelized and run on four CPUs instead of one. If ÃŽ ± is the fraction of a calculation that is sequential, and 1 − ÃŽ ± is the fraction that can be parallelized, then the maximum speed up that can be achieved by using P processors is given according to Amdahls Law:. Substituting the values for this example, we get If we double the compute power to 8 processors we get Doubling the processing power has only improved the speedup by roughly one-fifth. If the whole problem was parallelizable, we would, of course, expect the speed up to double also. Therefore, throwing in more hardware is not necessarily the optimal approach. WEAK v/s STRONG SCALING: In the context of high performance computing there are two common notions of scalability. The first is strong scaling, which is defined as how the solution time varies with the number of processors for a fixed total problem size. The second is weak scaling, which is defined as how the solution time varies with the number of processors for a fixed problem size per processor. EXAMPLES: A scalable online transaction processing system can be upgraded and can be used to produce more transactions by means of adding new processors, devices and storage that can be upgraded easily. It is also called as database management system. If the size of the necessary routing table on each node grows as O (log N) then the routing protocol is considered as scalable with respect to the network size where N is the number of nodes in the network. The distributed nature of the Domain Name System allows it to work efficiently even when all hosts on the worldwide Internet are served, so it is said to scale well. Some early peer-to-peer implementations of Gnutella had scaling issues. Each node query flooded its requests to all peers. The demand on each peer would increase in proportion to the total number of peers, quickly overrunning the peers limited capacity. Other P2P systems like Bit Torrent scale well because demand on each peer is independent of the total number of peers. There is no centralized bottleneck, so the system may expand indefinitely without the addition of supporting resources. SCALE VERTICALLY v/s HORIZONTALLY: Methods of adding more resources for a particular application fall into two broad categories: 1) SCALE VERTICALLY( SCALE IN): To scale vertically (or scale up) means to add resources to a single node in a system, typically involving the addition of CPUs or memory to a single computer. Such vertical scaling of existing systems also enables them to leverage Virtualization technology more effectively, as it provides more resources for the hosted set of Operating system and Application modules to share. Taking advantage of such resources can also be called scaling up, such as expanding the number of Apache daemon processes currently running 1) SCALE HORIZONTALLY (SCALE OUT) To scale horizontally (or scale out) means to add more nodes to a system, such as adding a new computer to a distributed software application. An example might be scaling out from one web server system to three. As computer prices drop and performance continues to increase, low cost commodity systems can be used for high performance computing applications such as seismic analysis and biotechnology workloads that could in the past only be handled by supercomputers. Hundreds of small computers may be configured in a cluster to obtain aggregate computing power which often exceeds that of single traditional RISC processor based scientific computers. This model has further been fuelled by the availability of high performance interconnects such as Myrinet and InfiniBand technologies. It has also led to demand for features such as remote maintenance and batch processing management previously not available for commodity systems. The scale-out model has created an increased demand for shared data storage with very high I/O performance, especially where processing of large amounts of data is required, such as in seismic analysis. This has fuelled the development of new storage technologies such as object storage devices. TRADEOFFS: There are tradeoffs between the two models. Larger numbers of computers means increased management complexity, as well as a more complex programming model and issues such as throughput and latency between nodes; also, some applications do not lend themselves to a distributed computing model. In the past, the price differential between the two models has favoured scale out computing for those applications that fit its paradigm, but recent advances in virtualization technology have blurred that advantage, since deploying a new virtual system over a hypervisor (where possible) is almost always less expensive than actually buying and installing a real one. CONCLUSION: Scalable system software has become an important factor to the RCF for efficiently deploying and managing our rapidly growing Linux cluster. It allows us to monitor the status of individual cluster servers in near-real time, to deploy our Linux image in a fast and reliable fashion across the cluster and to access the cluster in a fast, parallel manner. Because not all of our system software needs can be addressed from a single source, it has become necessary for us to use a mix of RCF-designed, open-source and vendor-provided software to achieve our goal of scalable system software architecture.

Father and Son Relationship, Angela’s Ashes Essay

One of the strongest things in this world is the love that forms between a father and his son. Many boys grow up with the desire to be just like their fathers but for Frank McCourt having an alcoholic father causes him to grow up with the mentality of being the opposite of him. In Angela’s Ashes the interesting relationship between Frank and Malachy creates positive and negative impacts on Frank’s life. At times, Frank despised his father for drinking the dole money but he knew that in the morning he would have his father to himself. Sitting on his father’s lap and hearing stories about Cuchulain was what made Frank feel loved. Although Malachy managed to make his son feel special, the sufferings that were caused by him made negative impacts on Frank’s life. One of the positive impacts that Malachy created for Frank was the Cuchulain story. Cuchulain symbolized Malachy’s fatherly side which only happened when he was sober. Cuchulain was something that Frank shared with his father which made it extremely special for him. He hold on to the memories he spend with his father and no matter how mad Frank was at Malachy he knew that the best thing to do was hold his anger in and not put their relationship in danger, â€Å"My heart is banging away in my chest and I don’t know what to do because I know I’m raging inside like my mother by the fire and all I can think of doing is running in and giving him a good kick in the leg and running out again but I don’t because we have the mornings by the fire when he tells me about Cuchulain and DeValera and Roosevelt and if he’s there drunk and buying pints with the baby’s money he has that look in his eyes Eugene had when he searched for Oliver and I might as well go home and  tell my mother a lie that I never saw him couldn’t find him† (McCourt 185). Frank knows his father’s addiction is what made the family suffer. The special moments that Frank created with his father was what stopped him from kicking him in the leg. Although Frank saw his father drink his little brother’s money, it was Frank’s love toward his dad that made him walk away from the pub. Malachy’s addiction affected the way Frank solved his problems. Since Malachy was always out in pubs it created a negative impact on his relationship with Frank. When Frank got troubled for hearing the word â€Å"piss† he turned to the Angel on the Seventh Step for help instead of his father. Malachy’s drinking often causes Frank to distance himself away from him during times where he was in need. Since Frank noticed that Malachy’s fatherly side only came out when he was sober he decided to seek help somewhere else. When he received help from the angel, Malachy felt the feeling of being denied by his son, â€Å"All right. Tell the priest if you like but the Angel on the Seventh Step said that only because you didn’t tell me first. Isn’t it better to be able to tell your father your troubles rather than an angel who is a light and voice in your head?† (McCourt 125). Malachy ruined the relationship he had with his son the moment he picked alcohol over his family. He turned his back to his family when they needed him the most. Frank was affected by his father’s addiction at an early age. Watching his father come home at night shaped Frank’s perspective on life. He often referred Malachy as the Holy Trinity because of his various attitudes, â€Å"I think my father is like the Holy Trinity with three people in him, the one in the morning paper, the one at night with the stories and prayers, and then the one who does the bad thing and comes home with the smell of whiskey and wants us to die for Ireland† (McCourt 210). Frank always found a way to have pity over his father but when he move to England, Frank no longer felt pity over him but anger. The moment Malachy stepped foot in England was the moment where Frank grew anger towards him. He was furious at his dad for being selfish and  causing his family to go through starvation. The negative impact that Malachy created caused Frank to get a job as a telegram boy. Since he was a lot older his mentality started changing towards his father. He no longer looked as his father as the one who made him feel special through the Cuchulain stories but as a selfish father who spent money on drinks. Malachy’s bad actions caused Frank to grow up with the mentality of being the opposite of his father. The bad example that Malachy demonstrated benefited Frank because it showed him what a man is not suppose to do.

Palmers Limited Case Study

Cost's they overlook the quality. While BC tries to look pretty to their customer, Cost pay less attention to their look and more to provide the lowest prices for their members. From 1997 to 2001, Wall-Mart store numbers were increased by 53, Bi's stores went up by 50, but Cost went up by 91 . Cost's business strategy Is very simple, â€Å"To generate high sales volumes and rapid Inventory turnover by offering members very low prices on a limited selection of nationally branded and select private-label products In a wide range of merchandise categories† (Thompson, 2008) .They have able to implement this strategy very successfully. They have also been very successful in making their customer believe that product is a better quality than their competitors, interestingly their competitors in most cases don't carry the same kind of product. Cost's marketing strategy is simple yet effective, the idea of providing the lowest price and good quality product is a strategy to be reckon with. Plus there marketing idea of â€Å"Treasure Hunt† has allowed them to saved tons of money from broad advertisement.After a membership base Is established In an area, most new memberships came from word of mouth. This simple marketing and advertisement strategy has allowed Cost to keep Its marketing expenses low relative to those at typical retailers, discounter, and supermarkets. Cost is also known for its price strategy. They have become a master in providing top quality products even including some brand products at the lowest price possible to their customers.Instead of marking up their cap to 20 or 50 percent like their competitors they decided to cap their mark up to only 14 percent, which itself a key element in Cost's pricing strategy. This also indicates that Cost is trying to do what it takes to please their customer to increase their profits so they can make their shareholders happy at same time. It's this price strategy that has allows Cost to only only make profit over the year, but Increase their member to $110. Cost's product selection strategy Is also very Impressive. Unlike their competitor who carry from where from 40000 to 1 50000 SKU items , Cost decided to selecting Ana prove only auto mess I en last Includes everyday Items sun as kitchen supplies, Electronics, health and beauty products, automotive supplies, gasoline, games, cleaning supplies, canned goods, Food. They categories their product in commercial and professional use. Plus, Cost's treasure hunt merchandising strategy is also an attention grabber. Out of the 4000 items on the floor about 1000 were the treasure hunt product, meaning their prices with constantly changing.In most cases these were higher end products like furniture and TV. Cost's growth strategy is also quite remarkable. On average they have been opening about 20 to 25 new stores each year. Most of them in American but some internationally as well including; Canada, Korea, I-J, Japan, Canada, and Mexico. In recent year they experimented by opening independent Furniture store to sell high end bigger furniture items which resulted in good success. Later rather than opening more stores they instead added extra space about 45000 square feet to the Cost it self and called it Cost Home.Now the furniture category has become on of the tope 5 selling items on Cost's website. They are very innovative when it comes to their warehouse and management strategy. Cost's CEO, Jim Senegal, quoted, â€Å"Cost is able to offer lower prices and deter values by eliminating virtually all the frills and costs historically associated with conventional wholesalers and retailers, including salespeople, fancy buildings, delivery, billing, and accounts receivable. We run a tight operation with extremely low overhead which enables us to pass on dramatic savings to our members†. They stored the inventory on racks above the items being sold in the warehouse. That reduced their labor cost and saved them a lo t time on handling and stocking. They treat their manager as entrepreneur and allows them to decide what item should be sold in their store. They adored most of the inventory directly from the manufactures. It either came directly to the store or went to their distribution center called crosschecking depots. The point of these depots were to reduce the transportation cost by making sure all truck are full when they come the store.As an investor I wouldn't would want to invest in a company that has a good reputation, consistently growing, good sustainable growth, and good future plans. Let's talk about sustainable growth rate, which basically means that a firm can grow while keeping its profitability and financial policies unchanged. Sustainable growth model allows us to segregate reasons or changes that have led as a company to substantial growth so at the same time we can segregate the causes for those change. It is represented in four steps.

How to Conjugate the Verb Uscire in Italian