ptg6432687 90 3 Planning, Sizing, and Architecting a Hyper-V Environment 5. For the Model Host Network Adapter and Memory, enter the configuration of your planned Hyper-V server network adapter configuration for speed of the adapters and number of adapters. Also enter the amount of RAM that will be in the server, such as 8GB or 16GB or 32GB. Then click Next. 6. If you leave Set Virtual Machines per Host unchecked, the Recommendation Wizard tells you how many of the physical servers you assessed will fit on this model config- uration you have created. If you check the check box, you can note whether you want two, three, four, or more virtual sessions on the system. Typically, you’d just let the wizard recommend how many sessions you want on the server, so you would leave the check box blank. Click Next to continue. 7. Import the text file you used in step 4 in the section “Setting Up the Microsoft VSA Tool to Capture Data for the First Time” that has the names of the servers you assessed. Then click Next. 8. Review your settings, and then click Finish. 9. The wizard will go through the worksheets that were created in the data gathering process, as well as go through the data captured and stored in the SQL server for the systems that were specified in the text file. This takes a minute or two, and you will then be prompted to click the Close button. From the Microsoft Assessment and Planning Solution Accelerator screen, choose the View Saved Reports and Proposals option. Doing so opens an Explorer window that shows the Excel spreadsheets and Word documents generated by the assessment tool. Open the ServerVirtProposal Word document that summarizes the recommendation on how many Hyper-V virtual servers would be needed, the expected CPU utilization of the servers, and the disk and network throughput of the servers. Combine the information from the Excel spreadsheet named ServerVirtRecommendation that notes a recommended split of servers between the Hyper-V host systems being acquired, and you get a good baseline recom- mendation on how to split the virtual guest sessions and what the anticipated workload will be on each of the host servers. Figure 3.9 shows some of the information from the reports. Analyzing the Workload Demands of Existing Servers Another way to review the workload and configuration of the servers in your environment other than using the Server Consolidation Recommendation Report is to open the Excel spreadsheet that is generated from the collection process. Excel spreadsheets are generated and dropped into the folder Documents\MAP\{database name}. Open the spreadsheet generated, and note the statistics about the servers being monitored. For network utilization, the report, as shown in Figure 3.10, notes the hostname, make and model of the network adapters in the system (if multiple network adapters are in the server, each adapter is assessed separately), bytes sent and received, packets sent and received, and packet errors. Download at www.wowebook.com ptg6432687 91 Analyzing the Workload Demands of Existing Servers 3 FIGURE 3.9 C Sample assessment metrics produced from the VSA tool. FIGURE 3.10 Sample network utilization report. Download at www.wowebook.com ptg6432687 92 3 Planning, Sizing, and Architecting a Hyper-V Environment For physical disk utilization, the report notes the hostname, the type of disk configured, total capacity of the disk, % disk read and write time, % idle time, average disk bytes/read and bytes/write, average disks sec/read and sec/write, and average disk queue length. The logical disk utilization report notes the hostname, disk volume name, total capacity of the drive, % disk read time, % disk write time, average disk sec/read and sec/write, and % free space. The statistical information provided in the spreadsheet along with the Server Consolidation recommendation report can provide valuable information about the server demands of the systems being assessed for virtualization. Identify Servers That Are and Are Not Virtualization Candidates With the recommendations from the Server Consolidation report and the data in the Excel spreadsheet, you can validate certain servers as good candidates for virtualization. These servers are likely the utility servers (DHCP, DNS, domain controllers), an assump- tion discussed earlier in the section “Candidates for Immediate Virtualization to Guest Sessions,” but are validated from the real-world statistical assessments. Other servers that might have been iffy as to whether they would be good candidates for virtualization can be validated from the statistics. You can confirm whether the workload, disk I/O, network I/O, or other server performance metrics data indicate the server is or is not a good candidate for virtualization. Combining Virtual Server Workloads to Create Optimized Host Servers From the data generated, combining server workloads together to logical host server configurations is the next step. Balancing servers so that all the servers with high proces- sor demands aren’t all put on the same host server but rather distributed across different host servers is the goal. The Server Consolidation report generated from the VSA makes suggestions on appropriate server balance. By combining the required memory statistic with disk and network I/O, the network administrator can now determine how many host servers are needed, how much memory each server should have, how many processors are recommended, and what type of disk and LAN configuration is recommended. Choosing the Hyper-V Host System Environment With the statistical data acquired from the Microsoft VSA analyzed and grouped together for optimum host configurations, the next task is choosing the host environment that Hyper-V will be implemented on. This is a decision whether the Hyper-V host will be implemented on a physical server or whether the Hyper-V host will be implemented on a blade server along with other physical servers or other Hyper-V host configurations. Download at www.wowebook.com ptg6432687 93 Sizing a Hyper-V Host System Without Existing Guest Data 3 Hyper-V on a Dedicated Host Server For organizations consolidating physical servers to virtual servers, usually an initial server used for Hyper-V virtualization is an existing server in the environment (typically a four or eight core system with a lot of memory, 16GB to 32GB). The system may have been earmarked for a database server or messaging server, but instead has been allocated as the host virtual server. Or the organization might have purchased the server specifically with host virtualization in mind. The dedicated physical server is like other servers on the network, with processors, memory, internal disk, and a network adapter or two. The system would be configured and have Windows Server 2008 x64-bit installed on it and have the Hyper-V role installed via the process covered in Chapter 4, “Installing Windows 2008 Server and the Hyper-V Role.” Hyper-V on a Blade Among Other Physical Servers Some organization may choose to purchase a blade server that is a physical server system with several server processor boards in the system. So instead of having a physical server with three or four virtual guest sessions running on it, the blade server has four or eight blades in the server, with one or more of the blades running as a Hyper-V host with three or four virtual guests running on the blade. Therefore, a blade server with 8 blades can run 8 different instances of Hyper-V host, and each Hyper-V host can be running 3 or 4 virtual guest sessions, thus allowing a single chassis to run 32 simultaneous server sessions. Blade servers can definitely consolidate servers down to a small footprint, where 32 physi- cal servers can end up in a single-rack chassis just 6 to 10 inches high. Sizing a Hyper-V Host System Without Existing Guest Data Although the exercise to assess the current workload of existing physical servers using the Microsoft VSA provides great metrics to size a Hyper-V host system for existing systems, the process of sizing the Hyper-V host system is not as precise for many organizations bringing up brand-new guest sessions without historical data. To take an educated guess at the sizing of the host system, since most servers in a data center are running less than 10% server utilization, there is typically plenty of excess server capacity available, and an administrator can take a pretty good guesstimates on server load. Because each virtual guest session is a completely running operating system, the installa- tion of as few as three or four high-performance guest sessions could quickly bring a server to 50% or 60% of the server performance limits. So, putting together a good educated guess is important in the process. Download at www.wowebook.com ptg6432687 94 3 Planning, Sizing, and Architecting a Hyper-V Environment Sizing Your Windows Server 2008 Server to Support Virtualization The host Windows 2008 server needs to run Windows Server 2008 x64-bit edition. Although the minimum requirements for server compatibility for Windows 2008 applies, because server virtualization is the focus of this server system, the minimum Windows 2008 server requirements will not suffice to run Windows 2008 virtualization. In addition, although Windows 2008 theoretically has maximum processor and memory capabilities that reach into a dozen or more core processors and hundreds of gigabytes of RAM, the reality on the scaling of Windows virtualization comes down to the raw capabil- ities of network I/O that can be driven from a single host server. In many environments where a virtualized guest system has a relatively low system utilization and network traffic demand, a single host system can easily support a dozen, two dozen, or more guest sessions. In other environments where a virtualized guest session has an extremely high system utilization, lots of disk I/O, and significant server communications traffic I/O, the organization might find a single host server maximizes its capacity with as few as seven or eight guest sessions. RAM for the Host Server With the lack of any other historical information, the rule of thumb for memory of a Windows 2008 server running Hyper-V is to have 2GB of RAM for the host server plus enough memory for each guest session. Therefore, if a guest session needs to have 2GB of RAM and there are three such guest sessions running on the host system, the host system should be configured with at least 8GB of RAM. If a guest session requires 8GB of memory and three of those systems are running on the system, the server should be configured with 24GB of memory to support the three guest sessions, plus at least 2GB of memory for the host system itself. Processors for the Host Server The host server itself in Windows 2008 virtualization has very little processor I/O require- ments. In the virtualized environment, the processor demands of each guest session dictate how much processing capacity is needed for the server. If a guest session requires 2 cores to support the processing requirements of the application, and 7 guest sessions are running on the system, the server should have at least 15 cores available in the system. With quad-core processors, the system needs four processors. With dual-core processors, the system needs at least eight processors. With Windows 2008 virtualization, each guest session can have up to four cores dedicated to the session, or processing capacity can be distributed, either equally or as necessary to meet the performance demands of the organization. By sharing cores among several virtual machines that have low processing needs, an organization can more fully utilize their investment in hardware systems. Disk Storage for the Host Server A host server will typically have the base Windows 2008 operating system running on the host system itself, with additional guest sessions either sharing the same disk as the host session or the guest sessions being linked to a SAN or some form of external storage for the virtualized guest session images. Download at www.wowebook.com ptg6432687 95 Sizing a Hyper-V Host System Without Existing Guest Data 3 Each guest session takes up at least 4GB of disk space. For guest sessions running databases or other storage-intensive configurations, the guest image can exceed 10GB, 20GB, or more. When planning disk storage for the virtual server system, plan to have enough disk space to support the host operating system files (typically about 2GB of actual files plus space for the Pagefile) and then disk space available to support the guest sessions. Running Other Services on the Hyper-V System On a system running Hyper-V, an organization would usually not run other services on the host system, such as making the virtual server also a file and print server, or making the host server a SharePoint server, or so on. Typically, a server running virtualization is already going to be a system that will maximize the memory, processor, and disk storage capabilities of the system. So, instead of impacting the performance of all the guest sessions by having a system-intensive application such as SharePoint running on the host system, organizations choose to make servers running virtualization dedicated solely to the operation of virtualized guest sessions. Of course, exceptions apply to this general recommendation. If a system will be used for demonstration purposes, frequently the host system is set up to run Active Directory Domain Services, DNS, DHCP, and other domain utility services. So, effectively, the host server is the Active Directory system. Then, the guest sessions are created to run things like Microsoft Exchange 2007, SharePoint 2007, or other applications in the guest sessions that connect back to the host for directory services. Planning for the Use of Snapshots on the Hyper-V System A technology built in to Hyper-V is the concept of a snapshot. A snapshot uses the Microsoft Volume Shadow Copy Service (VSS) to make a duplicate copy of a file; however, in the case of virtualization, the file is the entire virtual server guest image. The first time a snapshot is taken, the snapshot contains a compressed copy of the contents of RAM on the system along with a bitmap of the virtual disk image of the guest session. If the origi- nal guest image is 8GB in size, the snapshot will be significantly smaller in size; however, the server storage system still needs to have additional disk space to support both the orig- inal disk image plus the amount of disk space needed for the contents of the snapshot image. Subsequent snapshots can be taken of the same guest session; however, the way VSS works, each additional snapshot just identifies the bits that differ from the original snap- shot, thus limiting the required disk space for those additional snapshots to be just the same as needed for the incremental difference from the original snapshot to the current snapshot. This difference might be just megabytes in size. Taking into account whether snapshots will be used and how they will be used is impor- tant in sizing the Hyper-V host server because this will require more disk storage for the host system as more snapshots are taken and stored. Download at www.wowebook.com ptg6432687 96 3 Planning, Sizing, and Architecting a Hyper-V Environment Summary Microsoft Hyper-V is not necessarily difficult to install. Neither is it difficult to load up guest images to the system. To properly balance applications across multiple Hyper-V host systems, however, an administrator must do some simple performance assessment and planning. Common server images can be virtualized, such as domain controller services, DNS services, DHCP services, web services, and the like. And then there are server applications that aren’t as clear-cut as to whether they are good candidates for virtualization, such as database servers and clustered application servers. This chapter provided guidance that identifies servers that are commonly virtualized, and then provided information about the Microsoft VSA tool, which enables you to assess the performance demands of existing servers to calculate key server statistics that can be used to determine the workload of existing servers. With statistical information in hand, an administrator can analyze the information and determine how to best place virtual guest sessions across Hyper-V host systems. Best Practices The following are best practices from this chapter: . Distribute virtual guest sessions across host servers so that a host server isn’t over- loaded with too many guest sessions demanding processing speed, disk I/O demands, or network I/O demands, but instead is balanced in a logical manner. . Make sure to keep cluster pairs and redundant system services on separate host systems so that a host server failure doesn’t bring down both the primary and the backup image of a system. You should balance the services across separate host systems. . Consider keeping links server services such as frontend and backend servers on the same host system to improve the communication link speed between the two server sessions within the same host server. . Make sure to not centralize virtual guest sessions and cause remote users to have to traverse slow or unreliable WAN links to access their information. To maintain the quality of the user experience in the process, user access to information should be equal if not better than before servers were virtualized. . Plan for the number of virtual guest sessions you expect to have on a server to prop- erly size the host system with respect to memory, processor, and disk requirements. . Virtualize utility servers like DHCP servers, DNS servers, policy servers, and such that typically have low utilization and are redundant throughout an enterprise. Download at www.wowebook.com ptg6432687 97 Best Practices 3 . Evaluate whether certain servers such as file servers, print servers, global catalog servers, servers in a DMZ or edge, and media servers are good candidates for virtual- ization based on the organization’s workload of the systems. . Use the Microsoft VSA tool to gather server statistics on running servers during normal production hours to determine the overall usage of systems in the environment. . Assess the information that comes out of the Microsoft VSA to determine which servers are good candidates for virtualization and which servers are not as good of candidates for virtualization. . Combine statistical information of servers to determine the amount of memory, processor requirements, disk I/O, and network I/O of guest sessions to determine the proper size for each host system that’ll be added to the network. . Allocate enough disk space to perform snapshots of images so that the disk subsys- tem can handle both the required guest image and the associated snapshots of the guest session. . Consider keeping primary servers on physical server systems, and having secondary or redundant servers virtualized so that the organization can get the fastest perfor- mance on day-to-day queries against a physical server. However, the organization can have secondary servers as virtual server systems to minimize costs and consoli- date backup systems. Download at www.wowebook.com ptg6432687 This page intentionally left blank Download at www.wowebook.com ptg6432687 PART II Windows 2008 Hyper-V Host and Guest Installation IN THIS PART CHAPTER 4 Installing Windows 2008 Server and the Hyper-V Role Services 101 CHAPTER 5 Installing a Guest Session on Hyper-V 129 Download at www.wowebook.com . II Windows 2008 Hyper-V Host and Guest Installation IN THIS PART CHAPTER 4 Installing Windows 2008 Server and the Hyper-V Role Services 101 CHAPTER 5 Installing a Guest Session on Hyper-V 129 . to have on a server to prop- erly size the host system with respect to memory, processor, and disk requirements. . Virtualize utility servers like DHCP servers, DNS servers, policy servers, and. it and have the Hyper-V role installed via the process covered in Chapter 4, “Installing Windows 2008 Server and the Hyper-V Role.” Hyper-V on a Blade Among Other Physical Servers Some organization