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www.searchservervirtualization.comNetwork Consolidation                                   q WHAT’S INVOLVED IN            ...
WHAT’S     INVOLVED IN      NETWORK   CONSOLIDATION?                          What’s Involved in Network Consolidation?   ...
WHAT’S     INVOLVED IN      NETWORK   CONSOLIDATION?                          underutilized resources in physical servers ...
WHAT’S     INVOLVED IN      NETWORK   CONSOLIDATION?                          together, are also called an I/O director.  ...
UNDERSTANDING     CONVERGED    NETWORKING   AND VIRTUAL I/O                          Understanding Converged Networking   ...
UNDERSTANDING     CONVERGED    NETWORKING   AND VIRTUAL I/O                          Instead, MR-IOV provides the raw band...
MANAGING A    CONSOLIDATED       NETWORK      AND OTHER     CHALLENGES                          Managing a Consolidated Ne...
MANAGING A    CONSOLIDATED       NETWORK      AND OTHER     CHALLENGES                          new consolidated network. ...
MANAGING A    CONSOLIDATED       NETWORK      AND OTHER     CHALLENGES                          D Live migration. Network ...
GETTING    COMFORTABLE      WITH I/O   VIRTUALIZATION                          Getting Comfortable                        ...
GETTING    COMFORTABLE      WITH I/O   VIRTUALIZATION                               Although network consolidation allows ...
ABOUT THE       AUTHOR                                     Mike Laverick                                     is a professi...
RESOURCES FROM OUR SPONSOR• New Infrastructure 2011: Virtualization Advances in the Last 12 Months• Special Report: Your 2...
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IT Handbook - Network Consolidation


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Network consolidation can drive down costs, lower complexity and reduce the number of physical ports. Knowing its ins and outs is the first step to seeing these benefits.

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  2. 2. WHAT’S INVOLVED IN NETWORK CONSOLIDATION? What’s Involved in Network Consolidation? Network consolidation can drive down costs, lower complexity and reduce the number of physical ports. Knowing its ins and outs is the first step to seeing these benefits.WHAT’S INVOLVED INNETWORK CONSOLIDATION? any virtualization layer or hypervisor—whether it’s Citrix XenServer,UNDERSTANDING Microsoft Hyper-V or VMware ESX—introduces a new set of demands to aCONVERGED NETWORKINGAND VIRTUAL I/O server or blade environment. Although a hypervisor doesn’t need network access for its virtual machines (VMs), other interconnects do require networkMANAGING NETWORK access. A fully configured VMware ESX environment, for instance, couldCONSOLIDATIONAND OTHER CHALLENGES include the following networks:GETTING COMFORTABLE D ManagementWITH I/O VIRTUALIZATION D High availability D VMotion D Fault tolerance D IP storage (network-attached or iSCSI) D Backup Networks for fault tolerance or IP storage networks require additional 1 GB network interface cards (NICs) to achieve redundancy, and that requires sev- eral 1 GB interfaces on a standard 2U or 4U server and introduces expensive quad-port NICs. In some extreme cases, having those additional NICs can even dictate the type of server you must acquire. The number of ports needed would increase if your environment required additional redundant host bus adapters (HBAs) for Fibre Channel (FC) connectivity. Hardware vendors have developed a new model for connecting the host to both Ethernet and storage networks—network convergence, also called net- work consolidation. Similar to how server virtualization can consolidate many 2 N E T WO R K C O N S O L I DAT I O N
  3. 3. WHAT’S INVOLVED IN NETWORK CONSOLIDATION? underutilized resources in physical servers into VMs, network consolidation reduces many underutilized 1 GB NICs to two 10 GB or 20 GB cards. The cards are then separated into the necessary bandwidth for specific applications. Essentially, network consolidation aims to do for Ethernet and storage net- works what server virtualization does for the effective use of CPU and RAM— create one network to oversee them all. The whole process should drive downWHAT’S INVOLVED INNETWORK CONSOLIDATION? costs, complexity and the number of physical ports. Even a well-cabled rack that uses cable armatures and plastic ties can benefit from network consolidationUNDERSTANDING since fewer cables can improve airflow for cooling and extend cable shelf life.CONVERGED NETWORKING However, there’s more involved in network consolidation than simply a re-AND VIRTUAL I/O duction in the number of cables on data center racks. Network consolidation flattens conventional Ethernet and storage networks into one I/O transportMANAGING NETWORKCONSOLIDATION for all traffic. It also allows for greater consolidation ratios where increasedAND OTHER CHALLENGES reads and writes can become a bottleneck, as is the case on virtual desktops. Additionally, organizations can better use 10 GB Ethernet (10 GbE) networkGETTING COMFORTABLEWITH I/O VIRTUALIZATION cards, which should facilitate the migration to 10 GbE at a pace and price that suits them. Network consolidation also supports hypervisor-to-hypervisor communica- tions, which require low-latency links for tasks like live migration. If organiza- tions are using VM backups and pushing backup traffic through the network, you’ll see benefits there as well. Finally, this technology gives organizations greater freedom from previous limits of the PCI bus and allows more organizations to look at cheaper 1U and 2U servers for server consolidation projects. STEPS TO VIRTUALIZING YOUR NETWORK Replacing conventional 1 GbE network cards and 2 GB (or higher) FC devices with two 10 GbE devices is the first step in network consolidation. Combining these devices to create a single, redundant pipe to the physical world is next. That pipe is generally split between two physical switches that, when joined 3 N E T WO R K C O N S O L I DAT I O N
  4. 4. WHAT’S INVOLVED IN NETWORK CONSOLIDATION? together, are also called an I/O director. The physical host doesn’t detect these two 10 GbE interfaces directly. Instead, a virtual NIC (vNIC) and a virtual storage area network (vSAN) adapter are presented logically to the host. The network consolidation systems administra- tor defines these virtual devices, which look and feel as if they are physical devices; the physical server will also enumerate them as if they’re physicalWHAT’S INVOLVED INNETWORK CONSOLIDATION? devices. In many ways, this is similar to what some enterprises are doing with theirUNDERSTANDING VMs—allocating a VM to a vNIC even though the VM doesn’t realize thatCONVERGED NETWORKING there’s a virtual switch with a grouping of several physical NICs located behindAND VIRTUAL I/O the vNIC. Virtualizing the I/O layer makes the host more flexible than a VM. Most network consolidation systems come with built-in quality-of-serviceMANAGING NETWORKCONSOLIDATION and bandwidth management controls for handling the aggregated bandwidthAND OTHER CHALLENGES that 10 GbE interfaces provide. Figure 1 shows a simplified version of this con- cept; the numbers shown, which are expressed in megabytes, should not beGETTING COMFORTABLEWITH I/O VIRTUALIZATION taken at face value. I Figure 1: A redundant pipe will aggregate a specified number of megabits per second to each function. 2,048 Mbps 2,048 Mbps IP storage Backup 2,048 Mbps 2,048 Mbps Virtual machines Fault tolerance 100 Mbps Management 1,024 Mbps VMotion 100 Mbps HA heartbeat 4 N E T WO R K C O N S O L I DAT I O N
  5. 5. UNDERSTANDING CONVERGED NETWORKING AND VIRTUAL I/O Understanding Converged Networking and Virtual I/O The differences between converged networking and virtual I/O may seem subtle, but they can have a hugeWHAT’S INVOLVED IN impact on how you configure and manage your network.NETWORK CONSOLIDATION?UNDERSTANDINGCONVERGED NETWORKING there are two different approaches to network consolidation: converged net-AND VIRTUAL I/O working and virtual I/O. The approaches represent two different philosophies about how to consolidate the Ethernet and storage networks.MANAGING NETWORK Converged networking typically uses converged network adapters (CNAs) thatCONSOLIDATIONAND OTHER CHALLENGES not only provide bandwidth but also have advanced protocol support on the card. Cisco Systems, Emulex and QLogic are three vendors that favor this ap-GETTING COMFORTABLE proach, and it’s likely that HP, Dell and IBM will support these devices for theirWITH I/O VIRTUALIZATION conventional rack-mounted servers in the future. Converged network adapters generally support an iSCSI stack, along with TCP offload engines and other enhancements. Many also support Fibre Chan- nel over Ethernet (FCoE), which allows for communication from the appropri- ate switch layer to a legacy FC switch and storage array. CNA cards first gained marketplace visibility when some vendors adopted them for unified computing products, which bundle servers, blades, switches and management software and require customers to plug into existing storage arrays and networking. Converged networking generally uses the single-route I/O virtualization (SR- IOV) approach, which allows a single PCIe device to present itself as if it were several PCIe devices. By doing so, the hypervisor can natively use advanced protocols such as Fibre Channel, iSCSI and FCoE. Virtual I/O, on the other hand, adopts multiple router I/O virtulization (MR- IOV). In this case, there is no additional protocol support for the bandwidth. 5 N E T WO R K C O N S O L I DAT I O N
  6. 6. UNDERSTANDING CONVERGED NETWORKING AND VIRTUAL I/O Instead, MR-IOV provides the raw bandwidth to an external management sys- tem or I/O director. These cards, when fitted to the server or multi-initiator connectors (MIC), support advanced functionality such as InfinBand. However, that’s an optional component of the cards. A new breed of companies, including Xsigo Systems, NextIO, Egenera and Virtensys, favors the virtual I/O approach. The intention is to extend the PCIeWHAT’S INVOLVED INNETWORK CONSOLIDATION? bus out of the server chassis to an exter- nal I/O management layer that passes traffic onto an iSCSI or FC array. Virtual The main purpose ofUNDERSTANDINGCONVERGED NETWORKING I/O deliberately avoids the need to en- virtual I/O is to avoidAND VIRTUAL I/O capsulate particular protocols or access the need to upgradeMANAGING NETWORK mechanisms to the PCIe card itself. In- PCIe cards in everyCONSOLIDATION stead it externalizes these protocols from server to take advan-AND OTHER CHALLENGES the physical host. tage of new features. The main purpose of virtual I/O is toGETTING COMFORTABLEWITH I/O VIRTUALIZATION avoid the need to upgrade PCIe cards in every server to take advantage of new features and better support. It introduces a modular approach so that these upgrades can occur when the business wants them to, without affecting individual physical servers. Both converged networking and virtual I/O present a virtual device with a virtual media access control (vMAC) address—as if they are physical Ethernet devices—and a virtual worldwide name (vWWN) address—as though they are FC devices. This method allows the host to use the device natively, as if it were a true physical device. Frequently, the management systems of both approaches allow a central pool of vMAC and vWWNs to be allocated to groups of servers. To easily configure these virtual devices, the management system frequently has a profile or tem- plate that an administrator can allocate to physical servers, either individually or in groups. Allocating these profiles and templates can speed the process of setting up new servers in a rack. I 6 N E T WO R K C O N S O L I DAT I O N
  7. 7. MANAGING A CONSOLIDATED NETWORK AND OTHER CHALLENGES Managing a Consolidated Network and Other Challenges Introducing any method of network consolidation comes with several challenges. Answering the questionWHAT’S INVOLVED IN of who’s in charge can be the biggest obstacle.NETWORK CONSOLIDATION?UNDERSTANDINGCONVERGED NETWORKING introducing network consolidation into the enterprise is not withoutAND VIRTUAL I/O challenges, and the biggest stumbling block can be a lack of clarity about which department will actually manage it. Should the person in charge of the hypervi-MANAGING NETWORK sor, who understands how the physical server uses the consolidated networkCONSOLIDATIONAND OTHER CHALLENGES devices, manage it? Should the network team or the storage team be in charge of managing the consolidated network? One could argue that the network andGETTING COMFORTABLE storage teams should both manage the consolidated network in unison.WITH I/O VIRTUALIZATION Another administrative model could evolve in which the hypervisor manager becomes the overall “virtualization manager,” taking charge of both the hyper- visor and the consolidated network. Some smaller organizations already use this dynamic, but it may take some time for these true lines of responsibility to develop in large data centers. No matter your stance, the management question is unavoidable and the an- swer may have nothing to do with technical expertise and everything to do with IT department politics. And once you figure out who will oversee the virtual network, that person must become familiar with some of the other manage- ment challenges involved in network consolidation. D Compatibility and hypervisor configuration. Whether you use an automated process to roll out new server racks or entire data centers, you may need to re- view your scripts and other automated tasks to ensure compatibility with your 7 N E T WO R K C O N S O L I DAT I O N
  8. 8. MANAGING A CONSOLIDATED NETWORK AND OTHER CHALLENGES new consolidated network. Depending on which vendors you’ve chosen, you may have to apply a template to the server and install agents or drivers so that various virtual devices can communicate with the host and the hypervisor. You’ll then need to configure the hypervisor. There are two ways to configure an advanced hypervisor—use either VM- ware Host Profiles or PowerCLI scripts. With Host Profiles, the administratorWHAT’S INVOLVED INNETWORK CONSOLIDATION? can combine the hardware profile and hypervisor profile on the server without the need to use complex scripting languages.UNDERSTANDINGCONVERGED NETWORKINGAND VIRTUAL I/O D Proper terminology. It may also be neces- Network resource sary to adopt a common language across pools allow for some the IT department to avoid confusing theMANAGING NETWORKCONSOLIDATION consolidated network with other existing level of overcommit-AND OTHER CHALLENGES pieces of the infrastructure. Using the ment—similar to the wrong terminology can adversely affect way in which someGETTING COMFORTABLEWITH I/O VIRTUALIZATION management efforts. hypervisors manage Most virtualization vendors have re- memory. source pools that let administrators carve up blocks of memory and CPUs to more accurately meet management needs. Using a method similar to server virtual- ization, network consolidation provides a network resource pool that lets ad- minis carve up a block of bandwidth. Network resource pools allow for some level of overcommitment—similar to the way in which some hypervisors manage memory. With VMware, it’s possi- ble to assign more memory to a VM than is physically present on any host. This practice is safe, as long as IT monitors and manages it carefully. Memory overcommitment saves an enterprise from having to buy physical memory upfront when it may not be needed. The analogous feature in network consolidation is I/O oversubscription at the host level, which allows for tem- porary bursts of network traffic without having to buy end-to-end 10 GbE connections. 8 N E T WO R K C O N S O L I DAT I O N
  9. 9. MANAGING A CONSOLIDATED NETWORK AND OTHER CHALLENGES D Live migration. Network consolidation has its own version of live migration— the hypervisor’s ability to move a VM from one host to another with no down- time. Network consolidation presents vMAC and vWWN addresses to the physical server, which means these ad- dresses are no longer hard-coded to the server. Network consolidationWHAT’S INVOLVED INNETWORK CONSOLIDATION? Therefore, the live migration of I/O and I/O abstraction from one management system to an- will open the door for other is possible, enabling upgradesUNDERSTANDINGCONVERGED NETWORKING administrators to plug and maintenance without downtime.AND VIRTUAL I/O In the future, this technology may also VMs into any number lead to live migration of I/O for per- of network clouds—MANAGING NETWORKCONSOLIDATION formance reasons. without worrying aboutAND OTHER CHALLENGES how the network isGETTING COMFORTABLE D Network clouds. In the future, ad- connected to physical ministrators should be able to concep-WITH I/O VIRTUALIZATION cables. tualize the role of network consolidation to create a network cloud. Much of the debate surrounding cloud computing focuses on moving a business’s VMs and data from internal servers to external data centers run by service providers. There has been little consideration, however, on how the providers will actually manage the networks. Network consolidation and I/O abstraction will open the door for administrators to plug VMs into any number of network clouds—without having to worry about how the network is connected to physi- cal cables. I 9 N E T WO R K C O N S O L I DAT I O N
  10. 10. GETTING COMFORTABLE WITH I/O VIRTUALIZATION Getting Comfortable with I/O Virtualization Don’t let the idea of deploying network consolidation make you uneasy. Learn the terminology and do some researchWHAT’S INVOLVED IN on its methods to better prepare yourself.NETWORK CONSOLIDATION?UNDERSTANDINGCONVERGED NETWORKING network consolidation is an emerging technology that can trip up even theAND VIRTUAL I/O savviest IT teams. For example, enterprises inevitably will confuse converged networking and virtual I/O approaches and view them as the same technology.MANAGING NETWORK Although the outcomes of both approaches are fairly similar, they differ in phi-CONSOLIDATIONAND OTHER CHALLENGES losophy and execution. It’s also easy to confuse network consoli-GETTING COMFORTABLE dation with existing technologies from main- Deploying networkWITH I/O VIRTUALIZATION stream blade vendors such as HP Virtual consolidation will Connect, Dell FlexAddress and IBM Open cause many enter- Fabric Manager. These technologies address prises a good deal of issues that affect data centers using blades, anxiety, just as x86 but improvements must be made so that the virtualization did. technologies can offer features like network consolidation, and that will take time. Deploying network consolidation will cause many enterprises a good deal of anxiety, just as x86 virtualization did when it was first introduced. Major fears can center on staff training and IT department politics. How to roll up driver updates into existing best practices for patch management can also cause jittery nerves, as can a concern for individual host failures when running a hypervisor. Similarly, when a host uses few PCIe devices for networking, its failure can be that much more significant from an availability standpoint. In this situation, improved monitoring and alarms are needed so that IT staff can react quickly to device failures. 10 N E T WO R K C O N S O L I DAT I O N
  11. 11. GETTING COMFORTABLE WITH I/O VIRTUALIZATION Although network consolidation allows for I/O oversubscription, many virtual I/O vendors don’t offer ways to manage it. From a strategic perspective, some organizations use a single-vendor solution in which the servers, network and the storage are sold together, as opposed to a best-of-breed approach. Enterprises might perceive that theres a risk associ- ated with this type of vendor lock-in; how-WHAT’S INVOLVED INNETWORK CONSOLIDATION? ever, the flip side is that choosing smaller, more independent vendors in order to The urge, need andUNDERSTANDING avoid lock-in could also leave admins feel- pressure to virtualizeCONVERGED NETWORKINGAND VIRTUAL I/O ing apprehensive about the long-term via- I/O is directly bility of those companies. proportional to the Eventually, servers will begin reachingMANAGING NETWORK volume of I/O beingCONSOLIDATION the end of their warranties, making forAND OTHER CHALLENGES pushed around. some perfect opportunities for server ven- dors and network consolidation vendorsGETTING COMFORTABLEWITH I/O VIRTUALIZATION to introduce a new methodology. Additionally, the emergence of 10 GbE as a standard on most servers and blades will make network consolidation attrac- tive to large enterprises with big data centers. While I/O virtualization will still be an attractive option for small- and medium-sized enterprises, it has more bang for the buck in large enterprises. In the end, the urge, need and pressure to virtualize I/O is directly proportional to the volume of I/O being pushed around. I 11 N E T WO R K C O N S O L I DAT I O N
  12. 12. ABOUT THE AUTHOR Mike Laverick is a professional instructor with 17 years of experience in technologies such as Novell,WHAT’S INVOLVED INNETWORK CONSOLIDATION? Windows and Citrix. Involved with the VMware community Cathy Gagne Editorial DirectorUNDERSTANDING since 2003, Laverick is a VM- cgagne@techtarget.comCONVERGED NETWORKINGAND VIRTUAL I/O ware forum moderator and Jo Maitland member of the London VMware Executive Editor jmaitland@techtarget.comMANAGING NETWORKCONSOLIDATION User Group Steering Committee.AND OTHER CHALLENGES He is also the owner and author Colin Steele Site Editor of the virtualization website and csteele@techtarget.comGETTING COMFORTABLEWITH I/O VIRTUALIZATION blog RTFM Education, where Michelle Boisvert he publishes free guides and util- Managing Editor ities aimed at VMware ESX/ Virtual Center users. In 2009, Martha Moore Copy Editor Laverick received the VMware vExpert award and helped Linda Koury found the Irish and Scottish user Art Director of Digital Content groups. He has had books pub- lished on VMware Virtual In- Marc Laplante frastructure 3, VMware vSphere Publisher 4 and VMware Site Recovery Manager and was recognized ©2010 TECHTARGET. ALL RIGHTS RESERVED. again by being accepted into the vExpert program in 2010. 12 N E T WO R K C O N S O L I DAT I O N
  13. 13. RESOURCES FROM OUR SPONSOR• New Infrastructure 2011: Virtualization Advances in the Last 12 Months• Special Report: Your 2011-2013 Windows Server Environment• Creating a Business Case for Virtualization in the SMB Data CenterAbout Dell, Inc. and Intel:Dell and Intel have worked together for years to bring you end-to-end solutions that improvebusiness productivity, increase performance and reduce your total cost of ownership (TCO)across the enterprise.