Understanding processor, numa, core, logical processor and. All vcpus should be scheduled on the same numa node and, when possible, available vm. In windows server 2016, by default, how is numa configured. The use cases for this do exist but the problems they try to solve or the needs they try to meet might be better served by a different design or architecture such as dedicated hardware. With windows server 2012 hyper v became truly numa aware. Ive been asked a few times recently how to determine what virtual topology vnuma recommended and created for us and besides looking at the obvious guest os for the final result, you can also check the vmware. Virtual machine vcpu and vnuma rightsizing rules of. Hyper v and failover clustering page 2 introduction this document is part of a companion reference that discusses the windows server 2012. In a previous article, what is nonuniform memory access numa. If they know it they often could be helped by some more in depth information and examples on anything numa related in hyperv virtualization. Virtual numa support in hyperv 2012 hyperv 2012 introduces the concept of numa for virtual machines.
The numa node contains cores, and the core is the processing unit, its the physical core within the numa node. From the perspective of any single processor in the system, memory that is in the same numa node as that processor is referred to as local, and memory that is contained in another numa node is referred to as remote. This topic explains how to experiment with numa pinning and hyperthreading technology for pexip infinity conferencing node vms, in order to achieve up to. By default, the virtual numa topology is optimized by matching the numa topology of physical host. Socket sp3 platform numa topology for amd family 17h. Optimizing memory and ssd in server kingston technology. To fully optimize performance, however, additional steps are needed. All workloads running in a virtual machine must be scheduled for execution and the cpu scheduler handles this task with policies that maintain fairness, throughput, responsiveness, and scalability of cpu resources. Pdf modern shared memory multiprocessor systems commonly have nonuniform memory. In any case, it doesnt matter what you set the vm to if the underlying bios is broken, since hyper v will map virtual numa nodes onto whether the bios reports for physical numa nodes, and youre not going to get good performance until those physical numa nodes are described more usefully. Socket sp3 platform numa topology for amd family 17h models 30h3fh. Hyper v does not allow instances with a numa topology to have dynamic memory allocation turned on. The need or perceived need for hard cpu processor affinity stems from a desire to offer the best possible guaranteed performance. Hyperv manager shows 3 socketsnuma nodes available but.
Sql will read the numa topology and build its threads and memory allocation to match. As you can see, in the uma case, the cost of accessing a particular memory address is the same regardless of which socket your program is running on. The vm was configured with 16 procs, 2 numa nodes across 2 sockets and was live migrated to this new host. The topology within the virtual machine appears as a single numa node with all local memory, regardless of the physical topology. Understanding numa and virtual numa vnuma in vsphere anexinet. Despite having not enough functionality to serve large virtual environments, hyper v manager has attracted a great number of followers because it is userfriendly, intuitive, and licensefree. Numa best practices for dell poweredge 12th generation servers. Effectively, if you are cpubound but have io to spare, reducing the number of numa nodes is probably. When it comes to numa spanning and virtual numa in hyper v or anything numa related actually in hyper v virtualization this is one subject that too many people dont know enough about. Exposing a virtual numa topology into a virtual machine allows the guest os and any numa aware applications running within it to take advantage of the numa performance. Understanding numa and virtual numa vnuma in vsphere. If your company has an existing red hat account, your organization administrator can grant you access. Numa uses a construct of nodes in its architecture.
Oct 16, 2017 virtual numa and dynamic memory features cannot be used at the same time. Virtual numa support in hyper v 2012 hyper v 2012 introduces the concept of numa for virtual machines. Automatic numa balancing kernelbased virtual machine. Optimizing virtual machine scheduling in numa multicore systems. Windows server 2008 r2 hyper v and windows server 2012 hyper v 4 introduction the following tables compare selected features of windows server 2008 r2 hyper v and windows server 2012 hyper v. Due to a project i was working on, i had to hold off on sp1 for quite some time on my primary server. This blog is a consolidation one reference point to understand numa, vnuma, why it is important in the world of hypervisors. In the example below, there are two numa nodes sockets, each with a fourcore cpu with hyperthreading enabled. In the mathematical branch of topology, a hyperspace or a space equipped with a hypertopology is a topological space, which consists of the set clx of all closed subsets of another topological space x, equipped with a topology so that the canonical map.
In windows server 2012, hyperv presents a virtual numa topology to. Apr 28, 2016 when it comes to numa spanning and virtual numa in hyperv or anything numa related actually in hyperv virtualization this is one subject that too many people dont know enough about. Intel implemented it with the feature set quick path interconnect qpi in 2007 and amd implemented it with. A vms virtual cpus and memory are grouped into virtual numa nodes based on the underlying physical topology of.
The vnuma topology of a vm can span across multiple physical numa nodes. Both are memory optimization features of hyper v that have. Link nonuniform memory access numa has been with us for awhile now and was created to overcome the scalability limits of the symmetric multiprocessing smp cpu architecture. Aug 08, 2011 hyperv today is already pretty numa aware and as such it will try to get all memory for a virtual machine from a single numa node and only when that cant be done will it span across numa nodes. The new host has 2 sockets with 10cores hyper threaded. Windows server 2008 r2 hyperv and windows server 2012 hyper v 4 introduction the following tables compare selected features of windows server 2008 r2 hyperv and windows server 2012 hyperv. A vms virtual cpus and memory are grouped into virtual numa nodes based on the underlying physical topology of compute and memory resources. How to check uncheck allow numa spanning for hyperv host. Solaris and linux, ultrasparcfireplane and opteronhypertransport. Intel implemented it with the feature set quick path interconnect qpi in 2007 and amd implemented it with hypertransport in 2003. If for some reason your manual changes to numa settings result in poor performance you can use the handy use hardware topology button to.
The tables include comments about each versions performance, as well as a notation about how well each feature is supported. Ive never changed any of the numa configuration on our 2012 hyper v server, should i. Aug 31, 2015 hyperv dynamic memory versus virtual numa. If they know it they often could be helped by some more in depth information and examples on anything numa related in hyper v virtualization. Automatic numa balancing strategies cpu follows memory reschedule tasks on same nodes as memory memory follows cpu copy memory pages to same nodes as tasksthreads both strategies are used by automatic numa balancing various mechanisms involved lots of interesting corner cases. As the name suggests, numa refers to system memory ram and how we use memory and more.
It is primarily concerned with the placement of memory. Both windows and sql are fully numa aware and make scheduling decisions for threads based on the numa topology. After i did the upgrade, i decided to snoop around the hyper v manager a bit to see what was new and different. For those not familar, here is a onediagram numa explanation.
If your virtual machine does not use dynamic memory, then hyper v will reveal the physical numa architecture of the host that the virtual machine is occupying. In reality, the lack of a numa topology hasnt been an issue with hyper v in windows server 2008 r2 sp1 and earlier because the maximum number of virtual processors you can create within a virtual machine is 4. As a consequence, a copy of the original space x lives inside its hyperspace clx. Exposing a virtual numa topology into a virtual machine allows. By default, this virtual numa topology is optimized to match the numa topology of the underlying host computer. If you heard about hyperthreading sure you did, ht is the logical processor, and the logical processor is not a physical processor. Numa information provided to the guest os and applications improves overall application performance. I introduced numa and showed how hyper v works with it. Configuring hyper v virtual machine numa topology in this post i will show you how you can customize the virtual nonuniform memory access numa configuration of a virtual machine. Amd processors have had this type of architecture for some time with their hyper transport ht interconnects, while intel has begun implementing numa in their quick path interconnect qpi designs. Nonuniform memory access numa is a computer system architecture that is used. Cannot create a vm with more vcpu than the numa zone with cpu. Hyperv numa affinity and hyperthreading pexip infinity docs.
Numa spanning or nonuniform memory address spanning was a feature introduced into motherboard chipsets by intel and amd. On server1, you create a virtual machine named vm1. The processors are arranged in a ring topology resulting. Nonuniform memory access numa is a computer memory design used in multiprocessing, where the memory access time depends on the memory location relative to the processor. I recently made the jump to windows server 2008 r2 with sp1 in my home lab. Numa is becoming increasingly more important to ensure workloads, like databases, allocate and consume memory within the same physical numa node that the vcpus are scheduled. Linux cpu system topology, smp and numa fibrevillage. In windows server 2016, hyper v presents a virtual numa topology to virtual machines. Hyper v in windows server 2012 scale performance and density.
The getvmhostnumanodestatus cmdlet gets the status of the virtual machines on the nonuniform memory access numa nodes of a virtual machine host or hosts. It runs 2 vms and had only one processor that was a bit underpowered in my book so i found a pair of nice 6 core xeons and another 32gb of memory and bam, it made a nice difference in performance over the old 4 core xeon. Free vce and pdf exam dumps from passleader 70410 exam dumps 70410 exam questions 70410 pdf dumps 70410 vce dumps. When a virtual machine is sized larger than a single physical numa node, a vnuma topology is created and presented to the guest operating system. A numa topology b resource control c resource metering d. For more info on virtual numa, see hyper v virtual numa overview. Leave a reply, get the discussion going, share and learn.
Both are memory optimization features of hyperv that have. Resource controls provide you with several ways to control the way that hyper v allocates resources to virtual machine. Specifies how hyper v allocates resources to this virtual machine when more than one virtual machine is running and the virtual machines compete for resources. Explaining numa spanning in hyperv richard j green. Pdf modern shared memory multiprocessor systems commonly have non uniform memory. This document refers to the section titled hyperv and failover clustering and discusses virtual. Enabling dynamic memory in the settings of a vm disables virtual numa. The old host was an 2 socket 8core hyper threaded host. Under numa, a processor can access its own local memory faster than nonlocal memory memory local to another processor or memory shared between processors. Hyperv and failover clustering page 2 introduction this document is part of a companion reference that discusses the windows server 2012 hyperv component architecture poster. The numa api described here separates placement of threads to cpus and placement of memory. Visit passleader and download full version 70410 exam.
Esxi, and hyperv, is to allocate all the memory of a vm. If you heard about hyper threading sure you did, ht is the logical processor, and the logical processor is not a physical processor. The numa node is set of logical processors that has cache or memory that are close to one another. So as stated, hyperv with windows server 2008 r2 sp1 can prevent this form happening as we can disable numa for a hyperv host now.
This proposal describes a potential mechanism to support cpu affinity and numa topology. So long as the memory and cpu being used falls within the bounds of the numa node, local communication within a numa node allows a cpu much faster access to memory than in an ordinary system layout. Nonuniform memory access numa is a computer system architecture that is used with multiprocessor designs in which some regions of memory have greater access latencies. Hyper v can reveal the underlying physical numa topology to the vm so that the guest os and numa aware apps such as sql server efficiently assign memory and schedule processes to make the most of the boundaries. In smp, all memory access was tied to a singular shared physical bus.
May 27, 2014 ive been asked a few times recently how to determine what virtual topology vnuma recommended and created for us and besides looking at the obvious guest os for the final result, you can also check the vmware. The benefits of numa are limited to particular workloads, notably. Exposing a virtual numa topology into a virtual machine allows the guest os and any numa aware applications running within it to take advantage of the numa performance optimizations, just as. Numa spanning and virtual numa in hyperv working hard in it. Numa and smp are tuned differently, since you need to account for the topology of the system when allocating resources for an application. Read the starwind article to find out about numa spanning and virtual numa settings in windows server 2016 hyper v that allow large numbers of vcpus. This is due to how the system memory and processors are interconnected. Sep 22, 2016 when tuning application performance on a system with numa topology, it is therefore important to consider where the application is being executed, and which memory bank is closest to the point of execution. Exposing a virtual numa topology into a virtual machine allows the guest os and any numa aware applications running within it to take advantage of the numa performance optimizations, just as they would when running on a physical computer. A virtual machine that has dynamic memory enabled effectively has only one virtual numa node, and no numa topology is presented to the virtual machine regardless of the virtual numa settings. Configuring hyperv virtual machine processor and memory. A virtual numa topology is presented to the guest operating system. In a system with numa topology, the sys file system contains information about how processors, memory, and peripheral devices are connected. Numa best practices for dell poweredge 12th generation servers 7 for 4socket processor amd opteronbased systems, such as the poweredge r815 and m915, the numa layout becomes considerably more complex due to the fact that each physical processor package has two numa.
Is there a way to check uncheck allow numa spanning for hyperv host via powershell. The effect of numa tunings on cpu performance iopscience. Mar 20, 2014 configuring hyperv virtual machine numa topology in this post i will show you how you can customize the virtual nonuniform memory access numa configuration of a virtual machine. Hyper v uses acpi static resource affinity table srat to present numa topology to the vm. Numa best practices for dell poweredge 12th generation servers 7 for 4socket processor amd opteronbased systems, such as the poweredge r815 and m915, the numa layout becomes considerably more complex due to the fact that each physical processor package has two numa nodes. In previous posts, i have explained dynamic memory and nonuniform memory access numa. Hyper v manager is a microsoft application that is usually installed when the hyper v role is enabled on windows os. In addition, the application can configure cpu affinity separately. Numa best practices for dell poweredge 12th generation. If you are a new customer, register now for access to product evaluations and purchasing capabilities.
All the evennumbered cpu ids belong to one node and all the oddnumbered cpu ids belong to the other node. A numa architecture divides memory and processors into groups, called numa nodes. If you increase the number of numa nodes to a sql machine, it will spawn additional io threads. When dynamic memory is enabled, it effectively has only one virtual numa node and no numa topology is presented to the vm. Server1 runs windows server 2012 r2 and has the hyper v server role installed. Configuring numa in the settings of a hyper v virtual machine. Configuring hyper v virtual machine numa topology in this post i will show you how you can customize the virtual nonuniform memory access numa. When one speaks of the numa topology of a system, theyre referring to the layout of cpus. Hyper v automatically detects numa topology on a host and configures settings accordingly but if you have a cluster with servers of different. Numa spanning and virtual numa settings starwind blog. Hyperv manager shows 3 socketsnuma nodes available but there are only 2. By default, this virtual numa topology is optimized to match the numa topology of the underlying host. An important point to note about virtual numa is that it cannot be used at the same time as dynamic memory.
644 1054 1189 1483 1534 564 749 1434 779 127 1090 605 578 1587 729 77 1166 1022 1398 1371 1335 226 1313 1112 1161 1054 981 1084 252 935 962 1416