It is now the tax season in the US (the tax deadline being April 15th). This got me worrying a little bit about my income taxes, which led me to think about my IRA (Individual Retirement Account) contributions and also my checking and savings bank accounts. I was trying to figure out how much I should, or could, contribute to my IRA to reduce my tax burden, while at the same time having enough funds in my regular savings and checking account for expenses. As you may already know, once you deposit money in the IRA you have to wait until you reach 59 ½ years of age, otherwise there is a penalty for withdrawal. While having funds in a checking, savings or IRA account is good, there are tradeoffs for each. Having it in a checking account means I have ready access to my funds, but get no interest. On the other hand, an IRA provides for interest or investments, but does not provide quick access to the funds. A savings account is an in between.
Having funds in different types of bank accounts is sort of similar to Storage Tiering and Automated Storage Tiering (AST) in particular. AST is a feature built into many of today’s disk subsystems that automatically moves data between different “tiers” of disk storage within the array. The goal of this capability is to optimize the use of the different storage technologies within the array so that frequently accessed data, which presumably requires the fastest performance, is placed on the highest performing (and higher cost) technology (e.g. SSD and/or fast Fibre Channel/SAS disks). This type of storage architecture is becoming increasingly popular with businesses that are looking to cut back on storage costs while decreasing the storage administration that goes into figuring out where data needs to be placed to optimize resources.
The most common error in tiered storage is the confusion between data classification, tiered storage and information lifecycle management (ILM). Although data classification is closely related to tiered storage, the two are different. Data classification is the process that identifies data and determines its value to the organization. Tiered storage is the hardware, software and processes that actually implement those data classification plans while meeting the availability and performance requirements of the business applications.
Let’s look at the limitations of AST. First, AST algorithms are primarily based on access patterns and frequency, and not on the actual performance requirements of the applications. Second, AST does not guarantee that application performance SLA’s are maintained; only that an attempt will be made to minimize the response time of frequently accessed data blocks within the constraints of the array. Third, Storage Tiering does not understand application I/O performance requirements.
While there are clearly benefits to Automatic Storage Tiering it is still necessary to continuously measure I/O response time to ensure that the storage arrays are meeting the needs of the business. AST does not ensure that I/O transaction performance objectives are being met. It only provides a mechanism for optimizing performance within the constraints of the attached storage technology and the AST algorithms used. If the array does not have sufficient resources to meet the response time requirements of the applications, no amount of AST will be able to compensate for this deficiency. Real-time measurement and historical trending of response time via VirtualWisdom is still needed to ensure that the business’s needs are being met.
VirtualWisdom provides invaluable input to the architecture and design of a business’ tiered storage infrastructure. Whether the design applies to new arrays or upgrades to existing arrays VirtualWisdom provides a detailed understanding of workloads and response times, which allows storage architects to design a solution that meets the needs of the business in the most cost-effective manner. This eliminates the need to rely on rules-of-thumb and best guesses when designing a business’ infrastructure.
Virtual Instruments’ VirtualWisdom platform can help when you want to include Storage Tiering as part of your IT strategy. VirtualWisdom continuously measures critical application performance in real time ensuring that the SLA’s specified in the data classification plans are maintained. It optimizes the tiered storage infrastructure by ensuring that storage transaction performance is aligned with the most cost-effective storage technology. Further, it ensures that the storage tiering infrastructure is aligned to the requirements of the business.
“Not buying VirtualWisdom for your SAN is like hospitals not buying heart monitors,” VI customer.
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