Expert Tips for Consolidating Servers & Avoiding Server Sprawl


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Today servers are being moved to a single data center which presents a unique challenge for IT professionals, who have to handle numerous servers and business processes with a decreasing budget. The good news is that there are several practical ways to address these problems and keep servers as cost-effective as possible. In this expert e-guide from, find out how using server virtualization can cut costs.

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Expert Tips for Consolidating Servers & Avoiding Server Sprawl

  1. 1. E-GuideExpert tips for consolidatingservers and avoiding sprawlToday servers are being moved to a single data center which presentsa unique challenge for IT professionals, who have to handle numerousservers and business processes with a decreasing budget. The goodnews is that there are several practical ways to address theseproblems and keep servers as cost-effective as possible. In this experte-guide from, find out how using servervirtualization can cut costs. Discover a checklist with 8 cost-effectiveserver strategies. And learn how to devise a server consolidation planto prevent server sprawl. Sponsored By:
  2. 2. E-Guide Expert tips for consolidating servers and avoiding sprawl E-Guide Expert tips for consolidating servers and avoiding sprawl Table of Contents Using virtualization for cost-effective servers FAQ: Devising a server consolidation plan About Dell and MicrosoftSponsored By: Page 2 of 15
  3. 3. E-Guide Expert tips for consolidating servers and avoiding sprawlUsing virtualization for cost-effective serversBy Stephen J. Bigelow, Senior Technology WriterEverything old is new again -- at least when it comes to data center computing. Earlymainframes presented a centralized computing strategy, but this eventually gave way to adistributed computing model where servers appeared in departments and branch offices.Today, the proverbial pendulum has swung back toward a centralized model where serversare being moved to a single data center. This presents a unique challenge for ITprofessionals, who are often called on to support an ever-increasing number of servers andbusiness processes with a decreasing budget. The good news is that there are severalpractical ways to address these problems and keep servers as cost-effective as possible.It might seem like IT professionals would be eager to embrace any technologies that allowtheir companies to optimize IT operations, but the economic slowdown has made themhesitant to invest in any new changes -- even those that could improve efficiency."Lets say I can save $100,000 over the next two years in capital expense and some of myoperating costs," said Scott Gorcester, the president of Moose Logic, an IT technologyprovider in Bothell, Wash. "The problem is that its going to take a $100,000 project to dothat."Centralizing all of an organizations computing assets in one location can mean even greaterchallenges for existing data centers, such as space limitations, along with shortages ofpower and cooling. But perhaps the biggest issue for data centers is wasted processingpower. Experts say that most traditional servers running basic business applications operateat only 5% to 10% utilization, leaving the bulk of computing resources unused. As newapplications and services are added to data centers, the need to reduce waste and saveresources is critical to improving server cost-effectiveness.Sponsored By: Page 3 of 15
  4. 4. E-Guide Expert tips for consolidating servers and avoiding sprawlVirtualization in server cost-effectivenessServer virtualization has emerged as a preeminent data center technology that can improveutilization and address cost-effectiveness. Virtualization converts each application andoperating system to a unique virtual instance or virtual machine (VM) while disconnectingthe instance from the underlying server hardware, drivers and other elements thattraditionally tied hardware and software together.By mounting numerous VMs on the same physical server, data centers can dramaticallyconsolidate server use. This reduces the number of physical servers as well ascorresponding facility needs. Virtualization also offers data centers greater flexibility,allowing easy VM migration between even dissimilar physical servers to maintain availabilityduring server failures or planned downtime. The key for data center administrators is tobalance consolidation with performance and failover protection.Because virtualization potentially supports several VMs on a given server, use of theservers computing resources is significantly higher. Its not uncommon to find a virtualserver using 50% or more of its computing resources. The cost benefits of virtualization arewell understood: There are simply fewer servers, and each virtualized server can performmore business work per dollar spent on hardware, power, cooling, management andmaintenance.But the combined computing demands of VMs can tax even the most powerful server. Cost-effectiveness doesnt mean excessive consolidation; rather, it means balancing workloadsbetween multiple servers. If youve got two workloads -- one thats CPU-intensive and onethats memory-intensive -- together they may be good fits on a single server forvirtualization purposes, said Bob Plankers, a technology consultant and blogger for The LoneSysadmin.As multiple workloads attempt to access the same disk channels, disk I/O is anotherconstraining factor. Storage is often passed to an iSCSI or Fibre Channel storage areanetwork for better performance, less contention and more data protection. Current servermodels can usually receive CPU, memory, disk, or network upgrades to accommodateSponsored By: Page 4 of 15
  5. 5. E-Guide Expert tips for consolidating servers and avoiding sprawladditional or particularly demanding virtual workloads. Upgrades can be an economicalmeans to extend the life of servers and hold off costly technology refreshes.A server thats offline or crashed is extremely cost-ineffective, so keeping the virtual serverrunning and accessible is a crucial consideration in hardware cost-effectiveness. Manycorporations need their business operations running 24/7, especially to support globaloffices, customers or partners, from a single data center. To achieve availability in virtualservers, data centers should have redundant physical design elements such as powersupplies, network cards and fans as well as a certain amount of load balancing and failoverplanning.Although it seems counterintuitive, data centers should never seek 100% utilization onvirtual servers. Instead, they should leave an ample amount of processing capacity availableto assume the processing burden of other machines. This strategy helps eliminate singlepoints of failure.Just consider what would happen if a data center had two servers, each running five VMsand using close to 100% of server capacity. If one server failed, there would be no spareprocessing capacity on the companion server and the affected VMs would remain offlineuntil the server was restored.Ideally, a data center would want about 50% headroom on each server so that all the VMscould run on a companion server. As another example, if three servers ran VMs, about one-third more headroom would be needed on each server.Similarly, data centers should plan the process for VM failover. Tools like VMwaresDistributed Resource Scheduler can recover failed VMs from storage and recover on othermachines with available computing resources. But it always helps to apply rules andrestrictions to prevent incompatible VMs from inadvertently coexisting on certain servers.Fault-tolerance software provide even more availability by hosting redundant instances ofcritical VMs on clustered servers. When one server fails, the duplicated VM instance takesover without interruption.Sponsored By: Page 5 of 15
  6. 6. E-Guide Expert tips for consolidating servers and avoiding sprawlOptimizing hardware for cost-effective server utilizationCost-effectiveness often means getting more utilization from server hardware, but thisrequires insight about each servers hardware, the ways that hardware is utilized by eachVM and the underlying operating system hypervisor. Performance monitoring tools can trackand report on the computing resources needed by each VM. Several third-partyperformance monitoring products are available, but the major hypervisor vendors offersuitable tools. For example, VMware Infrastructure 3 provides an SRVC tool that can reporton a wide range of resources consumed by a VM (see Figure 1).Figure 1Hypervisor products like VMware Infrastructure 3 provide monitoring tools thatcan track and report on a systems resource utilization.Sponsored By: Page 6 of 15
  7. 7. E-Guide Expert tips for consolidating servers and avoiding sprawlOnce the resource demands of a VM are identified, it is also possible to tailor many of theserver resources made available to that VM using native hypervisor tools like Hyper-VManager (see Figure 2). As an example, it is possible to adjust the number of CPU cores,the amount of memory and other server resources allocated to a VM. Less critical VMs canreceive fewer resources, while vital ones can be configured to receive more. More VMs canbe supported while forestalling costly upgrades or outright server replacement.Remember that a virtual server should always reserve some unused headroom toaccommodate VMs failed over from other troubled servers, so upgrades and VM loadbalancing may be needed to ensure adequate computing capacity. Generally speaking,headroom recommendations shrink as the total number of servers increases because it ispossible to spread out the failed-over VMs across a greater number of physical servers.Figure 2Sponsored By: Page 7 of 15
  8. 8. E-Guide Expert tips for consolidating servers and avoiding sprawlHypervisors can also provide tools to tailor the allocation of computing resourcesto virtual machines to optimize server resources.Its important for data center administrators to consider the implications of VM sprawl,which is the unchecked proliferation of VMs across servers. VMs are so easy to create that anew one can be started in a matter of minutes. If not monitored and controlled, VMs can taxserver computing resources and create excessive VM management headaches that impairthe cost-effectiveness that virtualization can offer. Tools and policies can be implemented tohelp mitigate the effects of VM sprawl."There is still a pervasive approach toward deploying tactical management tools to controlVM sprawl to assist with maintaining the cost efficiencies that have been gained fromdeploying VMs," said Allen Zuk, the president and CEO of Sierra Management ConsultingLLC, an independent technology consulting firm based in Parsippany, N.J.So why not just upgrade the servers CPU, memory, disk subsystem or network adapter? Asecond CPU, for example, can be added to an available socket on a servers motherboard,or an existing CPU can be replaced with a faster model or one with additional cores,depending on the capabilities and limitations of the individual motherboard. Memory can beadded to unused slots or replaced with larger modules. Low-end SATA disks and controllerscan be replaced with high-performance SCSI disk systems or omitted in favor of networkstorage. Network adapters can be upgraded but are more frequently paired with a second orthird NIC installed on the server.Upgrades are easy to perform, but theyre also an easy way to waste money. The trick is todetermine the financial viability of each upgrade.Upgrades to CPUs and large memory modules can be expensive but can certainly be cost-effective when the server is new. Its also important to remember that upgrade componentsmay simply not be available for some proprietary systems, especially older proprietarysystems, or they may command a premium price that reduces the cost-effectiveness of theupgrade.Sponsored By: Page 8 of 15
  9. 9. E-Guide Expert tips for consolidating servers and avoiding sprawlConversely, it may be more cost-effective to allocate the upgrade cost toward a new server.A new server is certainly more expensive than upgrade components, and the labor neededto install and configure a new server can be substantial. But new servers often contain farmore powerful processors, chipsets and memory as well as a paid maintenance period. Thiscan make purchasing a new server more attractive than grappling with older servers thatare nearing a technology refresh."You might end up spending a couple of thousand dollars on more RAM for it, where youcould just apply that money to a much faster, more modern server," Plankers said. In manycases, the older server can continue to add value to the business by being reallocated to atest and development environment or a secondary environment.The value of used IT equipment should not be overlooked. Companies have quicklydiscovered that the poor economy has flooded the used-equipment market with loads ofslightly used top-tier servers at extremely competitive prices. Data centers can affordablypurchase slightly older equipment that still provides three or four years of useful operation.Its not enough to simply provide computing resources to run important VMs. Optimizationfor cost-effectiveness should also take into account server and network failures and theirimpact on user productivity. Data center managers should review their server configurationsand network architectures and locate single points of failure.These single points of failure may be perfectly acceptable in secondary or nonessentialservers, and VMs running on those platforms can easily be restored on other availableservers. But core applications may demand greater reliability elements, such as redundantpower supplies, redundant network adapters or a server clustering strategy with fault-tolerant software. Data centers may host mission-critical VMs on a small number of highlyavailable servers while relegating noncritical VMs to older or less expensive systems.There is no doubt that the implications of cost and efficiency will weigh heavily on corporatedata centers long after the current economic downturn ends. Gorcester said he sees trendscontinuing in much the same way they are now: using any available tactics or technologiesto improve server efficiency and prolong the working life of server hardware. GorcesterSponsored By: Page 9 of 15
  10. 10. E-Guide Expert tips for consolidating servers and avoiding sprawladded that the value of used equipment points to the used-equipment market as a source ofaffordable top-tier equipment."Organizations may start looking harder at alternatives such as data center outsourcing andmanaged hosting services," Zuk said. "Lets not forget cloud computing is making significantstrides in establishing effective security for the cloud, thereby providing more flexibility inthe VM space."Checklist for cost-effective server strategies Take advantage of monitoring and reporting tools. Getting the most from your virtual servers requires insight into the computing resources needed by each virtual workload, so adopt software tools that can monitor and report on resource loads. Hypervisors normally provide built-in tools and controls that allow data center managers to adjust resource allocation to each workload. Maintain interoperability between tools and servers. When selecting tools and servers, pay attention to interoperability. This helps to ensure that one tool can monitor and report on all of the available servers, which is more cost-effective than juggling multiple different tools from a variety of vendors. Avoid VM sprawl. Virtual machines are easy to create, often leading to unnecessary proliferation across data centers. This translates into more management overhead and potential security risks that can reduce the cost-effectiveness of virtualization. Implement policies that define the conditions necessary for creating a new VM. Only a limited number of IT personnel should have authority to create and manage VMs. Dont overuse a servers computing capacity. Pushing server utilization to 100% may seem cost-effective, but high utilization levels may leave inadequate computing resources to handle VM failover from other servers. This can force important VMs to remain offline and unavailable for extended periods. Leave a suitable amount of resource headroom available on each server to carry some portion of the VM load from failed servers.Sponsored By: Page 10 of 15
  11. 11. E-Guide Expert tips for consolidating servers and avoiding sprawl Consider the timing in any upgrade plans. Upgrades are typically less expensive than new server purchases and can extend the working life of some servers. But it may not be cost-effective to fund upgrades on proprietary hardware or older servers that are nearing the end of their production lives. Depending on business needs and financial circumstances, it may be more cost-effective to invest funds for an upgrade in a new and more powerful server. Consider the disaster recovery implications of server virtualization. Backups are often problematic for nonvirtualized infrastructures, but VM protection can be much easier with the copy and migration features of virtualization. One way to improve the cost-effectiveness of virtual servers is to routinely migrate VM copies to backup or off-site storage. Allocate older servers to secondary tasks. Its a simple matter to extend the useful life of older servers by reallocating them from production to secondary tasks such as backup or test and development. Eliminate single points of failure in servers and networks. Inaccessible or offline servers are worthless, so take all reasonable steps to eliminate single points of failure within the server and a LAN. This is most important for servers and network segments handling mission-critical workloads.Sponsored By: Page 11 of 15
  12. 12. E-Guide Expert tips for consolidating servers and avoiding sprawlFAQ: Devising a server consolidation planBy Alyssa Wood, Assistant Site EditorServer consolidation is a main benefit of virtualization, but many admins struggle to developa server consolidation plan. How do you decide which servers to consolidate, and when?As you virtualize a data center infrastructure, take stock of resource requirements,performance needs and host capacities. Capacity planning and resource allocation areimportant elements of a server consolidation project, because the goal is to maximizecapacity and improve resource utilization.Server consolidation allows you to run multiple virtual machines (VMs) on a single physicalserver, which reduces hardware costs, saves data center space and improves resourcesharing. Most traditional servers use only 5% to 10% of their total computing capacity, butyou can run consolidated servers at nearly full capacity (although this isnt always a bestpractice).The responses to these frequently asked questions will help you create a serverconsolidation plan, decide which servers to consolidate and understand the benefits of aserver consolidation project in your virtual infrastructure.What are the benefits of a server consolidation project?There are many server consolidation benefits that come from server virtualization. Withproper server consolidation planning, you can increase physical server capacity utilization toabout 50% to 80%. And you can run a greater number of workloads on less hardware,which reduces data center power, cooling and hardware costs. Server consolidation makes iteasier to take backup snapshots of VMs and provide quick data recovery when VMs fail. Itcan also improve workload migration, management and intercommunication between hostsand VMs. In a server consolidation plan, you should consolidate less-critical servers first,then systematically consolidate more mission-critical workloads.Sponsored By: Page 12 of 15
  13. 13. E-Guide Expert tips for consolidating servers and avoiding sprawlIs a server consolidation plan only beneficial for large enterprises?No, server consolidation also benefits branch offices. Smaller offices are often ideal sites fora server consolidation project because they have lower resource utilization, andconsolidation reduces space and power usage. Server consolidation planning can alsoreduce spare desktops or low-end rack servers that waste resources. When a data centerhas fewer servers, they are easier to secure, particularly in small offices where physicalsecurity is a main concern.How should I start my server consolidation project?To determine the number of physical servers youll need, identify which applications requirecertain hardware and organize VMs accordingly. Instead of traditional tape-based backups,you should perform VM migrations for backup. Setting up a test environment is anothergood way to start server consolidation planning. Before you execute your serverconsolidation strategy, its important to understand the benefits and what the payoff will be.How can server consolidation planning benefit test environments?Test environments enable you to stay up to date on virtualization strategies. But serverconsolidation in test and development environments offer numerous other benefits thanhoning your virtualization skills, including accelerated deployment time for the intendedinfrastructure. You can maximize CPU and memory usage, optimizing resources understress testing. You can even save test VMs as templates for future environments or newhosts. Server consolidation also allows you to create consistency in a test environment andcreate uniform backups.How does a server consolidation plan prevent sprawl?Running multiple VMs on a single server prevents a common data center problem: theproliferation of servers in physical environments. But of course, with virtualization, you stillhave to consider and prevent VM sprawl. When you deploy new applications or assign taskstoo quickly, this over proliferation of VMs often happens. A server consolidation plan,Sponsored By: Page 13 of 15
  14. 14. E-Guide Expert tips for consolidating servers and avoiding sprawlhowever, helps avoid physical server sprawl by eliminating unnecessary servers in a datacenter.How can virtual systems management tools help my server consolidation plan?Virtual systems management tools can improve server consolidation planning. These toolsimprove server consolidation ratios through configuration management, VM management,workload automation and job scheduling. Important performance indicators include thenumber of physical servers retired because of virtualization, the percentage utilization ofresources and the number of VMs per physical server. With management tools, you cantrack and control resource allocation, dynamically manage VMs and dynamically balanceallocation between batch and online workloads.Sponsored By: Page 14 of 15
  15. 15. E-Guide Expert tips for consolidating servers and avoiding sprawlAbout Dell and MicrosoftFor more than 25 years, Dell and Microsoft have worked to deliver jointly-developedsolutions that simplify IT management, optimize performance and evolve the way yourbusiness operates. Since the very beginning of our long-term partnership together, Dell andMicrosoft have aligned to deliver customer-driven, innovative solutions that span the entireMicrosoft® product portfolio.Sponsored By: Page 15 of 15