Windows Server 2012: Server Virtualization

Transcription

1 Windows Server 2012: Server Virtualization Module Manual Author: David Coombes, Content Master Published: 4 th September, 2012

2 Information in this document, including URLs and other Internet Web site references, are subject to change without notice. Unless otherwise noted, the example companies, organizations, products, domain names, addresses, logos, people, places, and events depicted herein are fictitious, and no association with any real company, organization, product, domain name, address, logo, person, place or event is intended or should be inferred. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation. Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property Microsoft Corporation. All rights reserved. Microsoft is either a registered trademark or trademark of Microsoft Corporation in the United States and/or other countries. The names of actual companies and products mentioned herein may be the trademarks of their respective owners. ii

3 Contents CONTENTS... III MODULE 1A: VM SCALE Module Overview... 4 LESSON 1: SCALE UP OVERVIEW... 5 SCALE UP PREREQUISITES... 6 SCALE UP TECHNOLOGIES... 7 NUMA... 7 Dynamic Memory... 7 Resource Metering... 8 SR-IOV... 8 LESSON 2: NUMA... 9 INTRODUCTION TO NUMA PHYSICAL NUMA OPTIMAL PHYSICAL NUMA NON-OPTIMAL PHYSICAL NUMA GUEST NUMA Using Guest NUMA Guest NUMA and Failover Clustering LESSON 3: HYPER-V SCALE COMPARISON HYPER-V SCALE COMPARISON iii

4 Module Overview This module explains the scale up technologies in Windows Server 2012 for virtual machine (VM) deployments. The module provides details about non-uniform memory access (NUMA), which is the key scale up technology. It also compares the scale up options in Windows Server 2012 with the options that were available in previous versions of Windows Server. 4

5 Lesson 1: Scale Up Overview This lesson explains the design prerequisites for VM scale up in Windows Server It also describes the key technologies implemented in Windows Server 2012 that enable VM scale up. 5

6 Scale Up Prerequisites There are several key scale up prerequisites that are met when using Hyper-V in Windows Server 2012: Scale. The virtualization platform must be able to scale up more than just virtual processors; this includes memory support, performance, networking and communications, and access to storage. Live Migration. Scale up technologies must not have any negative impact on Live Migration capabilities. Performance. There must be clear and demonstrable increases in performance as the number of host processor cores is increased. For example, it is not acceptable to obtain only a 75 percent increase in performance for a 100 percent increase in the number of processor cores. Virtualized workloads. The virtualization platform must be able to support the virtualization of all workloads and must be able to scale up those workloads as required. This should include all workloads, such as and messaging, databases, and large-scale web applications. 6

7 Scale Up Technologies Hyper-V in Windows Server 2012 uses a range of technologies to help enable scale up for VMs. NUMA NUMA is the key scale up technology used to scale up VM deployments in Windows Server It is described in Lesson 2 of this manual. Dynamic Memory Dynamic memory enables Hyper-V to assign increased memory capacity to VMs on-the-fly, with no downtime. In Windows Server 2012, dynamic memory has been improved to include new minimum memory and Hyper-V smart paging features: Minimum memory. This enables Hyper V to reclaim the unused memory from VMs. Hyper-V smart paging. This is a memory management technique that uses disk resources as additional, temporary memory when more physical memory is required to restart a VM than is currently available. To minimize the performance impact of Hyper-V smart paging, it is only used when all of the following conditions are true: 7

8 o o o The VM is being restarted. There is no physical memory available. No memory can be reclaimed from other VMs running on the host. Resource Metering Resource metering helps to track historical data on VM resource usage. You can use this data in capacity planning, to help determine appropriate resource allocations when scaling up VM deployments. SR-IOV Single Root I/O Virtualization (SR-IOV) support in Windows Server 2012 enables Hyper-V to assign an SR-IOV virtual function, of a physical network adapter with SR-IOV capability, to be assigned directly to a VM. This increases network throughput and reduces network latency while also reducing the host CPU overhead required for processing network traffic. 8

9 Lesson 2: NUMA This lesson introduces NUMA, which is the key technology for scaling up VMs in Windows Server The lesson explains physical NUMA on the Hyper-V host server and how you can optimize it. The lesson then describes how to use guest NUMA on VMs. 9

10 Introduction to NUMA NUMA is a technology that helps to manage the potential contention that might occur when multiprocessor computers attempt to access memory through the system bus. With NUMA, memory and processors are grouped into nodes: Local memory is attached directly to the processor. Remote memory is local to another processor in the system. Processors can access local memory faster than they can access remote memory, and in an optimal NUMA architecture, memory access across nodes is minimized or eliminated. 10

11 Physical NUMA Physical NUMA refers to the use of NUMA technologies to help any server workload make efficient use of processor cores and memory. With memory and processors grouped in nodes, the allocation of CPU and memory resources is made with best locality the system will always attempt to use memory that is in the same local node as the processor. High-performance applications such as Microsoft SQL Server 2012 and Internet Information Services (IIS) 8 in Windows Server 2012 are NUMA-aware, enabling significant performance enhancements over applications that are not NUMA-aware. With Windows Server 2012 Hyper-V, virtualization is also now a NUMA-aware workload. For example, when SQL Server starts up, it checks the underling topology and determines how best to carry out thread allocations, and memory allocations, to ensure that it is not hopping NUMA nodes. 11

12 Optimal Physical NUMA With optimal NUMA, memory allocation and thread allocations are all within the same NUMA node, and memory is populated in each NUMA node. This means that all the NUMA transactions, and all of the memory and CPU allocations, are occurring within the same NUMA node. 12

13 Non-Optimal Physical NUMA When NUMA is not in an optimal state, the system is imbalanced. In the example shown in the figure, there are several non-optimal configuration issues: Memory allocation and thread allocations occur across different NUMA nodes. There are multiple node hops. NUMA Node 2 has an odd number of memory modules; an odd number of modules may prevent memory interleaving, depending on system configuration. NUMA Node 3 does not have enough memory. NUMA Node 4 has no local memory; this is the most significant issue because all access to memory is going to be remote, impacting performance and limiting scalability. Note that although remote memory access was a more significant issue when systems relied on the front-side bus for processor-memory communication, even with the development of memory controllers on the processor, "node hopping" should still be avoided if at all possible. 13

14 Guest NUMA Windows Server 2012 provides guest NUMA support within the VM. Guest NUMA presents a NUMA topology within the VM that is consistent with the physical NUMA topology; specifically, the default virtual NUMA topology is optimized to match the host s NUMA topology, as shown in the figure. With the projection of the host NUMA topology onto the VM, the VM's operating system can interrogate the NUMA using industry-standard calls. This means that for any supported operating system in Hyper-V (including Linux), the VM's operating system can be auto-adjusted and be the most efficient for that NUMA topology, and when scale up applications are installed on that VM, these applications can also take advantage of NUMA. Hyper-V uses the Advanced Configuration and Power Interface (ACPI) Static Resource Affinity Table (SRAT) as the mechanism to present topology information for all of the processors and memory describing the physical locations of the processors and memory in the system. Important: Guest NUMA support for VMs running in Windows Server 2012 only works when dynamic memory has not been configured on the Hyper-V host. 14

15 Using Guest NUMA When a new VM is created using Windows Server 2012 Hyper-V, Hyper-V determines the underlying host NUMA topology and then automatically creates an optimal guest NUMA. However, using advanced options, administrators can choose to manually configure the guest NUMA topology and reconfigure NUMA nodes. There is also a "reset" option, so that manual settings can be automatically returned to the system-created automatic configuration. Guest NUMA and Failover Clustering Guest NUMA support also works for high-availability solutions using Windows Server 2012 failover clustering. Failover clusters evaluate the NUMA configuration of a node before moving a VM; this ensures that the target node is able to support the VM's workload. This NUMA-awareness helps to reduce the number of failover operations and, therefore, increases VM uptimes. 15

16 Lesson 3: Hyper-V Scale Comparison This lesson explains the new capabilities in Windows Server 2012 Hyper-V that enable significant improvements in VM scale up compared with previous releases of Hyper-V. 16

17 Hyper-V Scale Comparison New, and improved, capabilities in Windows Server 2012 Hyper-V enable significant improvements in VM scale up compared with previous releases of Hyper-V. Processors and Memory Hyper-V in Windows Server 2008 R2 supported configuring VMs with a maximum of four virtual processors and up to 64 gigabytes (GB) of memory. To support large, demanding workloads such as online transaction processing (OLTP) databases and online transaction analysis (OLTA) solutions, Hyper-V in Windows Server 2012 expands support for host processors and memory and includes support for VMs with up to 64 processors and one terabyte of memory. On the Hyper-V host, logical processor support has increased from 64 in Windows Server 2008 R2 to 320 in Windows Server 2012, and host memory support has increased to four terabytes. In Windows Server 2008 R2, the recommended ratio for virtual to host processors was 8:1 for servers, and 12:1 for client Virtual Desktop Infrastructure (VDI) deployments. With Hyper-V in Windows Server 2012, these limits do not apply. 17

18 Clustering The number of servers in a cluster has increased from 16 in Windows Server 2008 R2 to 64 in Windows Server 2012; this applies to both physical machines and VMs, so that you can now cluster up to 64 VMs. Live Migrations Windows Server 2012 introduces support for Live Storage Migration. For both Live Migration and Live Storage Migration, there are no built-in limits to the number of simultaneous migrations; you can migrate as many machines as the host hardware can support. 18