Application Performance Optimization and Load Balancing

Application Performance Optimization and Load Balancing Application Performance Optimization and Load Balancing using RAID and Caching Techniques Akilesh Kailash Sunil Iyer Kolar Suresh Kumar Sabarish Venkatraman ABSTRACT As the data processing and demand for storage grows, the performance of a critical application should always be intact with respect to disk I/O. There has been considerable improvements related to disk seek, latency and spindle speeds; However, these improvements have not met the challenges and addresses the need for better performance and load balancing. The challenge of any Database administrator is to maximize the Application I/O performance and ensure the high availability with zero downtime. This performance challenge can be met using I/O monitoring, Load balancing, Cache management and RAID (Redundant Array of Inexpensive Disks) technologies. The primary goal of this paper is to exemplify the details of successfully solving the I/O problems of a database application in a consistent fashion with the appropriate RAID configurations, caching mechanisms and load balancing algorithm. Categories and Subject Descriptors B.3.2 [Design Styles]: Mass storage – RAID. D.4.2 [Storage Management]: Secondary storage, Storage hierarchies. D.4.3 [File Systems Management]: File organization. D.4.4 [Communications Management]: Input/Output. D.4.5 [Reliability]: Backup procedures, Fault-tolerance. General Terms Algorithms, Performance, Design, Theory, Reliability. Keywords RAID Redundant Array of Inexpensive Disks I/O – Input/Output DBA Database Administrators HA High Availability OLTP Online Transaction Processing. IOPS HBA 1. INTRODUCTION RAID technology addresses the need for higher storage capacity in IO system and provides the feature of data redundancy. This helps in efficient and improved disk access and avoids data loss by disk failures. Theoretically, RAID is mainly used to create a logical disk from two or more physical disk drives in order to provide high bandwidth. RAID is an imperative part of storage stack and fabric layer and is coordinated by various storage vendors like EMC, Hitachi, NetApp. RAID technologies have enumerated different methods in building storage stacks and sub-systems for different kinds of databases. Thus, the two main technical reasons for switching to RAID are scalability and high availability in the context of I/O and system performance. As the database sizes of today have grown manifold from the gigabytes to petabytes range, the intricacy to scale I/O performance of such gigantic systems is needed very much for critical applications. Load balancing is a critical factor in environments like Operating Systems, Clusters, Networking and Applications. They play a quintessential role in the performance and reliability of any environment avoiding catastrophic failures. In a quotidian scenario, the resource allocation and load balancing are done through hash methods, genetic algorithms and several scheduling algorithms in Operating systems. Many database applications demand high throughput and availability from storage subsystems. For instance, a stock market application running in New York stock exchange will need to have a high throughput and bandwidth with absolutely no downtime. This requires continuous operation i.e., the need to satisfy each I/O request even in the case of disk failures. It is not acceptable to meet the aforementioned requirements at the cost of deprived performance mainly in real-time applications such as video and audio. It is highly unacceptable if a video is played at slower speed or the data is lost during transmission and ends abruptly. Since a database application may encounter extreme I/O activity or suffer a sudden spike of I/O activities for a brief period of time, the organization of the database structure onto the disk becomes imperative. 2. PROBLEM DEFINITION Mission critical data centers have a compelling need to have highly available applications and services thereby ensuring zero downtime. Current clustering solutions, like MSCS or HP Service Guard enable HA for vital applications. However, such applications are specific and developed only for the OS/application for which they are designed. The I/O performance and their patterns of a database application has to be analyzed by understanding their relation with the physical storage so that it helps in determining the deployment of application based on any given workload. I/O from an application needs to be categorized based on which appropriate techniques can be used in order to improve its performance. There are many DBA tuning software which are primarily used for indexing the database and monitor the drive activities. This approach is effective but requires lot of time and in reality it is quite tedious in nature. 3. ABSTRACT SOLUTION The possible solutions are: Determining the RAID Level and stripe size RAID levels are determined on factors such as type of I/O, disk cost, read/write I/O and so on. The data transfer rate and IOPS performance is very much influenced based on the segment size chosen and the striping size used. For example: In a RAID 5 configuration, there are 4 disks and 1 parity disk. Let the segment size of each disk be 64KB. Thus, when an I/O of 64KB has to be addressed, it is written to the first drive. The next I/O of 64KB is written to next and so on and finally the parity of the 4 I/O’s is calculated and written to the last disk. In case of RAID 1 (Mirroring), there are 2 disk groups and 2 mirror groups. A 64KB I/O would be written to each of the disk drives and mirrored drives. Caching techniques Splitting the cache The cache acts as an interface between the host application and RAID controllers. The cache can be divided into two parts viz. front-end and back-end. Database applications can rely on the front-end cache. Prefetching OLTP applications may have I/O operations which are not sequential; the pre-fetch algorithm confirms the addresses which will fetched in future and loads it in memory. The amount of data to be pre-fetched depends on the application requirement, memory and performance desired by application. Database organization on a storage system Organizing the database objects such as tables, logs, views on storage layout comes in a wide range. Based on the structure of the database layout, an appropriate storage is chosen. Load Balancing I/O load balancing across cluster nodes are performed using regression analysis. If a port of an HBA or fabric node is loaded heavily, then the I/O is balanced across the ports which are not utilized to its full potential. 4. LITERATURE SURVEY I/O performance and disk I/O contention plays a vital role for critical applications. Our proposal and work on application performance monitoring and I/O tuning and load balancing is motivated based on the â€Å"Oracle I/O Performance† and â€Å"Array tuning Best Practices† paper. The proposed solution and enhancements are based on similar lines of these papers. We start off the survey by explaining the technical feasibilities, the pros and cons of these approaches discussed in the papers and explain in brief about the issue we are addressing based on the survey findings. 5. PERFORMANCE BOTTLENECKS Application performance and write access is generally obtained by using storage Arrays having different RAID configurations. For instance, the striping of data across multiple disks using RAID 1 in order to achieve redundancy is the most common way of obtaining high availability. Disk failure vulnerabilities in enterprise storage The main motivation of going for striping technologies is because of the vulnerability in disk failures in enterprise storage Arrays which can result in catastrophic loss of data. This high availability of application and I/O is obtained at the cost of write performance. Keeping synch of write operations During a write operation, all the writes have to be updated simultaneously to all the disks in order to keep the disks in synch. This will have a catastrophic result in operations which will have heavy writes and its performance. In addition to it, maintaining the synchronization of data between all disks and achieving concurrency is a difficult task and can lead to system crashes. In order to overcome the aforementioned problems; a number of different striping mechanisms have been proposed; each of them have their specific tradeoff based on cost, high performance, scalability and robustness. The majority of RAID configurations are based on the interleaving of the data and the pattern is which the redundant information is distributed across the disks. Load Balancing of I/O and resource utilization Load balancing is essentially implemented in SQL server clustering and is very common practice. There are many third party tools that provide solutions to load balancing and resource utilization; however the limitations of such tools is that the factors to decide on load balancing are very system specific and are dependent heavily on the characteristic of each application. As the database size grows in a short period, we generally observe that the query speed has a performance hit as the number of rows increases. This is mainly observed on applications where the performance data is being collected in frequent intervals and simultaneously the data is read from the DB for other purposes. The general and quick solutions to optimize query speed it to partition the views, indexing and table partitioning. But even then, things are observed to be quite slow. The main problem with such solutions is that the database tables and views are located on different servers. Hence a server cluster is used which add in reliability if there is any performance issues seen on one of the cluster nodes. 6. RAID LEVEL SELECTION CRITERIA The choice of RAID level to be chosen is based on different factors. When a mirrored configuration is chosen such as RAID 1 or RAID 1+0, each write request is duplicated to disk by the raid controller. This results in performance issues if the application does not rely heavily on data duplication and its availability. When higher levels/parity based RAID configuration is used, things get more intricate. Let us consider that, when RAID 5 or RAID 6 is used and if the size of the write I/O is less than the stripe size which is frequently observed in database applications where the data write is around 4kb pages contrasting to the drive size of around 128KB; as a result of this, the raid controller has to perform magnitude of I/O operations for just a single request. The main drawback of the above technique is that for a small write request, the raid controller has to first fetch the data from the back end disk to the main memory. Then it has to insert the fresh data at the appropriate position and calculate the new parity stripe to perform another write operation back to the disk. Hence, one I/O operation results in roughly 3 to 4 times the IOPS. This overhead adds in if the calculation of parity is for two sets as in RAID 6. The other factors of choosing the RAID configuration are the disk/drive cost and I/O pattern. The cost is zero for RAID 0 as there is no redundancy; while it is highest for RAID 1 or its combination such as RAID 10. This cost is high because of drive mirroring. The cost of RAID 5 is comparatively lower than RAID 1 but it has one disk which is dedicated for parity. A cleared distinction is required to classify small I/O and large I/O. The bursty nature and large I/O is seen if the request for the I/O is more than the one third of the cache size. All the small/short I/O’s are addressed in cache thereby avoiding the RAID access. All in all, RAID 5 and 6 are generally preferred for large I/O and sequential I/O operations while RAID 1 and RAID 10 is preferred for short I/O operations. 7. SCOPE FOR IMPROVEMENT This paper goes on the aforementioned aspects and concentrates on monitoring the I/O pattern, analyzing the load on each of the I/O and performing a load balance if required; In addition to the above criteria, taking the I/O pattern into consideration, an appropriate RAID configuration along with write-back cache method is used if necessary. 8. PROPOSED SOLUTION Characterize the I/O pattern The first step is to monitor the I/O and characterize it. This is done using tools such as Perfmon or IO Meter. We plan to use these tools and analyze the I/O pattern of a given application. This monitoring of pattern is required as we will characterize the request as read intensive, write intensive, how the load is being varied. Perform load balancing upon I/O threshold The second step is to perform load balancing. This is done by analyzing the load and identifying the threshold of the I/O from a server HBA Port through the fabric layer to the storage Array. Threshold is a boundary which serves as a benchmark for comparison or guidance, and any deviation or breach of the said threshold may result in a change in state of an overall system. Our proposed infrastructure identifies the threshold by analyzing the I/O graph and monitoring the following parameters: Linear Regression Slope of the curve Using Linear Regression, the value of the slope is calculated. Based on these two parameters, if we observe that if one of the HBA ports is heavily loaded, we tend to balance it out by redistributing the excess load to different cluster nodes. Once the I/O is balanced, an appropriate RAID configuration is calculated. 9. CONCLUSION AND FUTURE WORK After studying the I/O access patterns of various workloads, we can clearly the map the database application to the physical storage thereby achieving high performance, fast access and retrieval. This would be helpful for DBA’s to deploy management applications and would be easy to track the application performance. This analysis can be implemented at the enterprise level configuration as well resulting in efficient usage of physical storage, making it cost effective and reducing the work for DBA’s or lab administrators. 10. REFERENCES The RAID Book: Sixth Edition. RAID Advisory Board. LACIE: RAID Technology White Paper. RAID: High-Performance, Reliable Secondary Storage – ACM Computing Surveys Peter M. Chen, Edward K. Lee. Array tuning best practices A Dell technical white paper DOI=http://www.dell.com/downloads/global/products/pvaul/en/powervault-md3200i-performance-tuning-white-paper.pdf. Exploring Disk Size and Oracle Disk I/O performance DOI= http://www.openmpe.com/cslproceed/HPW02CD/paper/11026.pdf

Overfishing Effects More Than Just the Ocean

Salmon migrate yearly from the open Pacific Ocean to the coastal areas of the Pacific Northwest in order to spend about 5-6 weeks reproducing. During this time bears also migrate to these coastal areas to feed on the salmon which is a large part of their diet. This natural interaction has been an important factor of the ecosystem in the Pacific Northwest for many years and now that humans have imposed on this process by overfishing we are seeing changes in the ecosystem itself. While knowledge of this issue has been around for about 30 years, scientists only began researching it beginning in the early 90’s. According to this research the ongoing problem of overfishing is already beginning to show its effects on the ecosystem, what may happen to the forests and animals of the Pacific Northwest if this issue is not resolved? Through the research of Dr. Tom Reimchen and other scientists, an interaction between salmon and the forests of the Pacific Northwest has been discovered. Each year black and grizzly bears travel from far away to the streams and rivers in the Pacific Northwest to feed on the salmon that migrate there during their six week spawning period. This causes a local interaction, when the bears catch a fish they take it into the forest so they can eat it and not be disturbed. Usually the bears only eat about half of each fish they catch and leave the rest on the forest floor, which is then consumed by birds, other small animals and insects. Through the decomposition of the salmon as well as the bodily wastes of the bears and other animals, the soil in the forest absorbs nutrients as well as nitrogen from the salmon. â€Å"The use of stable nitrogen isotopes allows us to identify the relative contribution of salmon to the ecosystem† (Reimchen 2001: 14), this research showed that nitrogen 15, an isotope of nitrogen is present in a large number of the plants in the Pacific Northwest forests. Nitrogen 15 is mostly found in marine algae and salmon are highly enriched with it so it makes sense that the plants use the remnants of the salmon as a sort of fertilizer to make them grow causing large scale interaction. The presence of the nitrogen in the plants of the Pacific Northwest forests does not mean that the plants necessarily need it to grow. In another experiment performed by Reimchen he sought to answer this question, â€Å"I examined yearly growth rings of 13 trees of similar size from sites differing in (salmon) carcass density. Average growth rate over the last 50 years was 2. 5mm per year within 10m of the stream where carcasses were most abundant and less than 1mm per year where carcasses were not present† (Reimchen 2001: 14). These results are debatable because other factors such as the amount of rainfall and sunlight they get effect plant growth too, but another observation which backs the theory that nitrogen helps the plants grow is that the amount of salmon brought into the forest by the bears each year varies directly with the amount of salmon coming back to the stream each year. In the conclusion of his research thus far Reimchen believes that if it is not stopped, â€Å"†¦ the result of deforestation and overfishing will have ecosystem-level consequences for the remaining forests† (Reimchen 2001: 16). Due to the overfishing of salmon by humans, the migrating salmon population has reduced 80-90 percent in the last 100 years. In nature predators and prey coexist in equilibrium, but with human interference the salmon can not reproduce fast enough to keep up with the amount being caught resulting in a large decrease in their population. Although there are programs like the MSY or maximum sustainable yield in place which tells fisheries how many fish they are allowed to catch, they do not factor in the natural predators of the salmon and therefore they throw off the balance of the ecosystem. A direct result of over fishing is the harvesting of salmon in fish farms, the salmon are raised in net pens that usually float in areas off the coast. The biggest problem with fish farming is the fish escaping into the wild, for example in 1997, 360,000 salmon escaped from a single farm off the Washington coast. The salmon raised on fish farms are, â€Å"†¦ ed concentrated feed and medication to maximize the conversion of feed into growth while minimizing the loss of fish due to disease and escape† (Reimchen 2001: 139), the effects of the salmon raised on farms escaping into the wild may be genetic, ecological, and can cause problems with disease and parasites. The genetic problems the farm salmon can cause are they will interbreed with wild salmon and disrupt their genetic adaptations, replacing their genetic variability and their evolutionary potential. The competition for food, space, and habitat between the farmed and wild salmon could also be a problem. Farmed fish sometimes get sea lice or ISA a contagious lethal virus that they can pass to the wild salmon. All of these factors are depleting the amount of wild salmon as well as altering the way the salmon live. Another contributing factor to the decline of the salmon population is the political ecology involved. On one side there are the people willing to do anything in their power to protect and restore the status of the salmon in the pacific northwest, but on the other more powerful side are the people who see the salmon as a huge money maker and are doing everything they can to continue overfishing so they can profit from it. The fisheries not only catch salmon so they can sell it locally, but where they get the most money from is shipping it to large grocery store chains across the country. They must overfish in order to meet the demands of the stores they supply or else the stores will go to another source for salmon, so many fisheries ignore the problem and continue overfishing because they think that if they stop someone else is just going to come in profit off of what they are not catching. The problem with overfishing and fish farms are not only harming the salmon population, but if nothing is done about these issues it will effect the animals in the pacific northwest as well as the vegetation. Black and Grizzly bears get around 75% of their yearly dietary requirements from the salmon, with the amount of salmon available becoming less and less each year the bears are not going to have enough to eat and their population will decrease as a result. I also think that with the introduction of the farmed salmon and the diseases they can carry the bears may get sick and die from eating diseased fish. With less bears the vegetation in the pacific northwest will also suffer because less salmon will be transferred into the forests where the plants can absorb the nitrogen and the plants will not grow as much or as quickly, it may also make the plant population less diverse. I believe that the overfishing needs to be controlled by more extreme measures so that the salmon can be allowed to reproduce naturally and keep their population up. If companies sold salmon raised in a fish farm at lower prices and raised the price of wild salmon this may help as well because the more expensive it is, the less people will buy and the fishing companies will not have to catch as many. Its kind of like how you can go to the store and buy either regular fruit or pay extra for organic, and there is always people who are willing to pay more. I also think that fish farms should not be integrated in the coastal waters, they should be in a completely different location than the wild salmon so there is no chance of them escaping and contaminating the wild salmon. In addition to the repercussions of fish farming and overfishing on the ecosystems in the Pacific Northwest forests, deforestation is another action by humans that is threatening this area. With the growth rates of the trees already falling due to lack of nitrogen from salmon and humans cutting them down at an alarming rate, it is inevitable that unless serious steps are taken to protect both the salmon and the forest itself from humans the ecosystem in the Pacific Northwest will fail and the forests will be completely destroyed. References 1)Frissell, C. (1995). Topology of Extinction and Endangerment of Native Fishes in the Pacific Northwest. Conservation Biology, 7. http://www.jstor.org/pss/2386432 2)Reimchen, T. (Fall 2001). Salmon nutrients, nitrogen isotopes, and coastal forests. Ecoforestry. 3)Sachs, J. (15, Jan. 2010). Icon for an Endangered Ecosystem. http:// www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2010/Icon-for-an-Endangered-Ecosystem.aspx

Cross Cultural Perspective †Nike Corporation Essay

Pakistan and Cambodia have strict child labor and slavery laws, however, the government has done very little to regulate it. Contracts for production are still being granted in areas of Pakistan where there is not sufficient monitoring or regulation to make sure that child labor laws are being observed and enforced. The United States Constitution deems that child labor is not only illegal but also inhumane and that any organization caught practicing or even encouraging forced labor or violating child labor laws will be prosecuted. The general thought process of Nike and many other global organizations is that they can operate their production with the lowest cost of labor. This leads the organizations to enter into violations of child labor laws. An investigation was conducted where Nike was found to have a large number of cases that involved forced labor or child labor law violations in some of the large apparel factories of Nike. In a particular factory in Malaysia, it was found that Nike was operating production in terrible working conditions for the employees in addition to the forced labor. It was found that Nike had underage children working in sweatshops up to seventy hours a week in unhealthy conditions making their products. Pakistan has a population of approximately 1 million people and it is also an important location or â€Å"hub† per say for the production of goods that are to be exported to international markets, this is especially true of the production and export of sporting goods which brings in revenues in excess of 300 million dollars a year. When confronted with the findings, Nike issued a statement stating that they would take corrective action to make sure that the child labor laws were followed and that they would not continue to operate forced labor and bad working conditions within any of their factories. Nike started focusing on their social responsibility efforts in areas in which they can have the greatest impact and create the greatest value for the organization and for the communities that the various factories are in. Nike has initiated the social responsibility efforts in the materials they design for their products, as well as the process of making those materials and products. An analysis of the ethical and social responsibilities Nike faced with global expansion had many factors that needed consideration. The first consideration was the cost of making their products. To stay competitive in their prices while not reducing the amount of employees, Nike, decided to outsource some of their manufacturing and suppliers on a global scale. This provided Nike cost advantage over their competition and it also allowed Nike to expand into emerging markets. Some could view this as unethical practice because it could take jobs away from manufacturing plants in the United States; however, Nike was acting in the best interests of the organization including its employees overseas and the employees back in the United States. If an organization does not maintain a competitive edge in their respective markets when expanding the organization not only in the United States but also worldwide, there would be no room for growth and jobs would be lost. When a company is no longer competitive in their respective industry, it can eventually cause them to shut down factories in their communities, which in turn can cause people to lose their of jobs. Nike’s social responsibility to the community includes the Nike Foundation. The Nike Foundation focuses on adolescent girls in developing countries. Nike has established custom product lines, marketing, events that have raised donations from consumers. Nike strongly believes that every young person in should have access to sports and has developed various programs and activities. Aside from the Nike Foundation, Nike has also developed several other programs as part of their social responsibility such as the Homeless World Cup (HWC), ninemillion and Let us Play in China. The Homeless World Cup (HWC) has supported locally-run football programs for homeless community members in more than 60 countries globally. In addition, 34 of these nations either plan or already have active national street soccer leagues running throughout the year (Nikebiz. com). The HWC training programs include technical training as well as assist the players with drug or alcohol dependency programs, finding jobs, finding homes and receiving education to name a few (Nikebiz. com). In 2006, NIKE, Inc. , partnered with the United Nations High Commissioner of Refugees (UNHCR) and Microsoft to launch the ninemillion campaign through ninemillion. org to give more than 9 million children living in refugee camps access to better education, sports and technology (Nikebiz. com). The let us play in China program has partnered with China Children and Teenagers’ Fund, under the government-organized NGO Women’s Federation, on a program that empowers migrant youth and introduces more child-centered teaching methods through sports (Nikebiz. com). The Nike Foundation’s mission is to provide innovative programs that offer solutions for girls, by partnering with larger organizations to get girls’ issues on the international agenda and to mobilize resources to support them (Nikebiz. com). This promotes learning skills and the ability to work as a team. It creates the ability to adapt to situations that could arise in the work environment and in life; it also promotes confidence in playing sports. This is one of the most ethical things that a company can do to help develop the next generation. In conclusion, Nike has accepted that they have done some things in the past that have been rather unethical and have been damaging to their image, not to mention that it could have really altered their profitability.

Antigone’s Purpose - 1224 Words

Brooks Fridey Antigone’s Purpose In the story of Antigone, originally written by Sophocles, explains the story, of a woman who stands up for her own beliefs against the king. At the time of Sophocles, women had little power and authority. They were expected to listen to their husband, king, or any man that speaks to or asks a woman of something. The story starts up where the story of Oedipus ends, in his death. Trouble and war are about to begin in Thebes, so Antigone travels there to try and stop what may become of her family and country. From my observations, this story can be analyzed in multiple ways, whether it is about the struggles of women, defying the higher power, or responding to the will of the gods. It is said†¦show more content†¦To Antigone, it is not necessary that someone should obey their leader at all times. She believes what Creon declared to happen to her brothers was unfair and that the gods were telling her she needed to bury her brother. Antigone was unapproved to the treatm ent of women in these times, and that the king must be obeyed in all causes. She believed the gods were the true powers, and bad things would come upon you if you did not cooperate with their requests. When Haemon comes into the story, acknowledged as Antigone’s fiancà ©e, who is the son of Creon, makes it clear why Antigone was even still alive. Although Creon was cruel and often harsh, there was still something or someone holding him back from simply killing her. Haemon told his father it would be wrong to kill Antigone and would bring great mourning to the people of Thebes following her death. He wants Creon to be open to others views, but Creon responds by calling Haemon a woman’s slave for backing up a woman and not his own father. A blind prophet advises Creon that he should properly bury Polyneices and release Antigone. He says if he does not he will greatly anger the gods, and might create his own misfortune for his disobedience. Possibly leading to hi s own death. As Creon ponders his possibilities and future, he finally decides to release Antigone and bury Polyneices. As he thought he was then making the right decision, he would soon find out what his