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Server Consolidation

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PCQ Bureau
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As organizations and their computing needs grow, they tend to accumulate servers, which get distributed across offices and departments. Over time, any organization can end up with servers of different configurations, some of them completely out of date, running a variety of OSs and applications. Since each server is individually purchased, there would be redundancies like extra CPU power, disk space and RAM built into each, which when added up could come to a lot. But, being on descrete systems, these are not

useable if any other system needs them.

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These are some of the many instances where server consolidation can be considered.

So, what is server consolidation? As the name indicates, it is the act of replacing multiple physical servers, perhaps at different locations, with one larger server.

Why consolidation?



You can resort to server consolidation to achieve one or more of the following objectives:

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  • Reduce hardware and software costs, including maintenance, upgrade and licensing costs.
  • Reduce total cost of ownership through more optimized staffing, training, space and environment (UPS, backup, airconditioning, etc) utilization and system management.\
  • Optimize server performance by faster application deployment and by creating more secure environments.\
  • Improve server utilization through higher utilization levels with layered platform software on fewer, more powerful servers.
  • Improve service availability by moving to platforms with high availability features like Active-Active clustering.
  • Reduce cost of support. Outdated servers cost a lot to maintain, and even more to upgrade. So, you might as well consolidate many of them at one time. Similarly, you many have “orphan” applications that cannot be migrated to newer OSes , nor have vendor support , and need to be rewritten afresh.
  • Even out resource availability. Newer servers would typically have extra disk space and the latest, fastest CPU, while older ones would be running out on space and efficiency. Similarly, servers bought in isolation would probably have accessories, such as backup devices, duplicated.

Server consolidation can have various approaches, each with its own benefits and pitfalls. Let us take a quick tour through the important features of the different approaches.

Centralization



This is the most basic and easiest consolidation, and involves moving most of the servers and resources from remote locations at a central or fewer locations having adequate bandwidth and support infrastructure. The benefits of doing so are reduced support and management costs, as support personnel, spares and contracts can be centralized and duplication reduced. It also makes implementing a disaster recovery solution easier and more manageable.

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However, centralisation does not cut down on the number of servers and would also entail

increased WAN dependence and usage.

Physical consolidation



Almost all consolidation studies by OS and server vendors extol the benefits of this consolidation. It involves replacing a large number of servers with a smaller number of enterprise class servers, with fewer, more robust

OSs.

Physical consolidation has many benefits including improved performance and application response times, increased availability and uptime since the solution would necessarily include enterprise class servers and, optionally, a highly available cluster.

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Depending on the situation, there could be a reduction in hardware and software costs and license fees. There will also be a reduction in environmental requirements for servers like rack space, UPS, air-conditioning, etc.

The drawbacks of physical consolidation would be a crash or downtime. This would be catastrophic, considering that many applications, especially if they are custom made or windows-based, might not easily coexist in a single server. Memory leaks, service pack and library version dependencies could easily cripple an otherwise hardware fault tolerant setup. The server could also fail due to a hardware fault. 

Hence, a highly available setup would be best in such a situation.

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Data or storage consolidation



Storage consolidation would involve centralized storage for all servers. This could also be clubbed with database consolidation or any other consolidation approach to maximize returns.

The benefits of implementing this include:

  • Increased usability, availability and performance.
  • Heterogeneous Servers and files systems can be accommodated.
  • Easier backup and restoration — even LAN-free or server-free policy based backup is possible.
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Such a setup would however involve a good amount of investment and planning. So, return on investment would have to be considered over a longer period of time of about three to five years. 

App consolidation



The most arduous of all consolidations, this approach attempts to consolidate most of your applications into fewer numbers. Its also synonymous with ERP (Enterprise Resource Planning). Although the benefits of such a consolidation are many, it’s a complex exercise that would require major investments and planning. Implementation would also stretch over a longer period of time than any of the other approaches. 

Should you go in for server consolidation?



To begin with, more insight needs to be gathered on your running servers and their usage. This should be as comprehensive as possible and should include details like server inventory, usage, utilization and support costs for each server.

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Server Inventory includes hardware configurations, operating system details, storage and storage availability, including the backup solution used.

Server Usage Information includes role and location of the server, software and databases used, number of users, availability and business criticality.

Server Resource Utilisation is memory, CPU and IO utilization.

This data can be analyzed to zoom in on islands. Islands are groups of servers that have common usage or requirement patterns and, hence, can be consolidated. For example, multiple mail servers or database servers or file and print servers or (multiple) departmental file and print servers can be consolidated.

There would also be servers that might be isolated and irreplaceable in function, for example, Firewall, security and antivirus servers might not be possible to consolidate.

Consolidation solutions



There exists many consolidation solutions ranging from specific hardware to software to OSs. The current trend is to use Big SMP (Symmetric Multiprocessing) servers that can be partitioned into smaller logical partitions.

Microsoft has newer OSs (the Windows 2003 family) in the offing that have better resource management tools such as the ability to define resources for multiple applications running simultaneously on a single large server, which are useful in a consolidation scenario.

There are also solutions offered by VMware (http://www.vmware. com) and Connectix (http://www. connectix.com) -the latter now being taken over by Microsoft — that can transform servers into multiple logical servers — each having dynamic resource management features and the ability to concurrently run different OSs with different applications as well.

Vmware’s ESX server is notable among these and has been around for a couple of years now.

Another trend now is to use Blade Servers. While Blade servers have been around for the last couple of years on the Intel platform, they have only just begun to get into the serious application and database server markets, with server class hardware.

Earlier, Blades used mobile processors and were restricted in resource scalability, due to heat restrictions. 

A Blade-based setup is not only rack-dense, but also works out cheaper when compared to standard rack-dense servers.

The reason for this is quite obvious - they do not duplicate common parts such as power supplies and cooling fans.

They also build in integrated management, KVM switches and Ethernet switches in the chassis as modules.

Fabian J D’Mello Pre Sales Technical Specialist, IBM eServer xSeries

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