How to solve storage management challenges in virtual world

As the volume of data grows, so does the need for storage. And it seems that the more virtualized a server needs more storage. As a result, both trends-data growth and virtualization-are becoming a powerful force for storage growth.

"Storage capacity continues to grow at nearly 60% a year," said IDC analyst Benjamin Woo, "2008 is likely to be a turning point in terms of application and storage interface." And the virtual server will become the iSCSI (Internet Small Computer system interface) killer application.

Does the virtual machine (VM) accelerate storage growth? According to Scott Mclntyre, vice president of Emulex software and customer marketing, administrators often give VMware large capacity storage configurations that exceed normal requirements. This configuration is like a storage pool, and then capacity allocation based on the requirements of the different virtual machines at the time of establishment. In fact, VMware actually encourages http://www.aliyun.com/zixun/aggregation/14290.html "> storage managers to configure capacities that exceed the physical requirements, such as 25% of the capacity of 20 virtual machines. It is easier to configure very much storage in a virtual environment.

In theory, this is to make storage more efficient by increasing usage rates. But is it possible to actually backfire?

"Virtualized environments that use VMware do not themselves need more storage capacity than their physical environment," said Jon Bock, senior product marketing manager for VMware. "A very important correlation is that customers often change how they use and manage storage in VMware environments, To take full advantage of the unique capabilities of VMware virtualization, their storage capacity requirements reflect this.

The current situation seems to be that companies are tweaking their own storage requirements to take advantage of features built into the virtual environment. For example, VMware's storage interface,--VMFS (virtual machine file system), provides snapshot capabilities that are used for online backups, to create archived replicas on virtual machines, and to provide a good copy to enable recovery in the event of a patch error, virus infection, and so on. Although you can do a lot of things with a virtual machine, you need more space.

Addressing management challenges

But the bigger problem may be management confusion, which comes from conflicts between virtual servers and virtual storage.

"How to reconcile virtual servers and virtual storage is a particularly tricky issue", "the trend towards enterprise-class data center virtualization, while providing many opportunities for effective management and energy efficiency, has also raised a number of new issues for IT managers," said Mike Karp, an analyst at the Business Management Consortium. ”。

In the final analysis, virtualization is the simplification of management through an abstraction layer. For example, storage virtualization is the hiding of physical storage complexity while rendering a simple file, logical volume, or other storage object (such as a disk drive) to an application, so that storage administrators and applications do not see this complexity.

But even in one area, such as servers, this "simple layer" can complicate things. Let's take a look at a traditional example of CPU measurement. We do IBM micro-partitions in an AIX (IBM UNIX System) synchronous multi-threaded (SMT) environment. In this environment, there are two virtual CPUs in a shared processor pool. The partition runs a process that consumes 45% of the physical CPU resources within a 60-second time interval. When you measure the environment, there are some problems. For example, in different situations, such as SMT enabled or closed, or processor usage is set to the top or no top, the results may be different.

CPU statistics%busy represent usage of virtual processor resources. In this case, the%busy may be 37.5%. So for another CPU measure, this time the LPAR (logical partition) is represented by%ENTC. %ENTC represents the authorized processor usage. %entc reached 75%. Observe another metric,%lpar_pool_busy, that represents the utilization rate of the processor pool. It's only 18.75%. Or look at the%lpar_phys_busy--physical processor usage. It was 9.38%. There are other indicators, and their results may be quite different.

"One capacity planner may see an indicator that the usage rate is low while the other person may have a completely different view of the different metrics," said Jim Smith, an enterprise performance expert at TeamQuest company in Iowa State Clear Lake. For virtualized processors, this is a difficult question to answer. Every answer may have the right side.

Some San best practices, such as logical unit number masking and virtual machine partitioning, Mclntyre said, "In addition, virtual Host Bus adapter technology allows virtual machines with different I/O loads to coexist without affecting their I/O performance." This hybrid load performance enhancement is important in a merged, virtual environment. In this environment, different virtual machines and applications access storage through the same set of physical host bus adapters.

There is no doubt that over time, more and more virtual artifacts and analysis tools will have to be added to the enterprise environment in order to fully utilize the virtualization functionality. Until then, we must be prepared to add complexity in the name of simplicity.

"To be able to identify the problem, and to proactively manage and prevent problems throughout the environment, it is very important to understand the topology in real time--or at least in real time--and Karp says," at best, every monitored process can use a continuously updated topology. "

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