Questions tagged [vcpu]

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vcpu counts aren't changing after config change and reboot

I recently downsized the number of vcpus virtual server Echobox1 uses from 4 to 1. before: # virsh vcpucount Echobox1 maximum config 4 maximum live 4 current config ...
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2 votes
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Set CPU affinity for specific VM on vmware ESXI using govc CLI

I have shell scripts that I use to programmatically configure my Virtual Machines (VMs) on my vmware ESXi host. I use the "govc" command-line-interface (CLI) which provides a suite of ...
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KVM with 1 vCPU has CPU load above 1

I have a KVM running with 1 vCPU on a machine with 4 cores. lscpu in the KVM gives me 1 CPU with 1 core : Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte ...
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-5 votes
1 answer
80 views

Google compute - Less vCPUs high IOPS vs More vCPUs low IOPS [closed]

My Postgresql databases are running on Google compute instances N1 with custom(26 vCPUs, 52 GB memmory) with a pessistent ssd disk 1.2TB . This setup is way underused, but keep the Read IOPS under 3k. ...
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How to load one physical CPU in a system with virtual cores?

I have an AMD processor with 4 physical cores and SMT enabled. Because of the latter, I see 8 virtual cores in a Linux box. For example, stress command can spawn a number of workers spinning on sqrt()....
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2 votes
2 answers
5k views

Azure VM Core vs vCPU

When comparing two different VM series in Azure, I see that one has Cores and the other one vCPUs. Keeping aside the number of Cores/CPUs, Memory and Processor Type (Intel Xeon E/Platinum etc), what ...
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9 votes
1 answer
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Do CPU credits exist for c5d.large instances? And if not, why not?

I've been paranoid that the websocket feed I was listening to on a t3.micro instance was being inhibited by cpu steal time from other instances under the same hypervisor. So I switched over to a c5d....
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how libvirt cputune config goes to qemu-kvm

I am porting xml libvirt config to qemu executable arguments. Simply I have .xml vm config from virsh edit vm-name and I want to run the same vm machine by executing qemu-system-x86_64 with special ...
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How to identify CPU(s) on Linux EC2 instance?

I'm running a Linux c5d.9xlarge instance and wondering what CPU it's using. Amazon's Instance Types webpage states: C5 and C5d 12xlarge, 24xlarge, and metal instances have the following specs: ...
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Google Cloud Configuration CPUs

I need to configure a machine on Google Cloud Platform (Brazil/Sao Paulo) to run a biometric service and my software provider requested a machine with the following specification: "2 x Intel® ...
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libvirt hot unplug cpu

I'm currently working with libvirt. after i reduce the number of vcpu cores with below command, the operation will be completed successfully. i should also mention that my current and max vcpus is 4, ...
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processor type differences between elasticache instance types , will all instances suffer the same way?

This may sound like yet another, "what is a vcpu" or "should I use elasticache, remember its single threaded!!" question --- but I think this asks a question unanswered. redis is single threaded, ...
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7 votes
4 answers
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How does the vCPU align with the CPU? (VM with more cores than the CPU has)

I have a VM running on vSphere 6.5.which has 24 vCPU's. The server has two physical cpu's (xeon e5-2699 v4) which have 22 cores and hyperthreading is enabled. How exactly are the vcpu's running on ...
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959 views

aws ec2 t2.small vs t2.medium CPU performance

Since t2.medium has 2 VCPU and t2.small has 1 VCPU would it be faster as a web server? (Apache/php). I am wondering if I upgrade if I will gain any performance benefits.
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Will More vCPU's and RAM Help Protect Against Some Smaller Scale DDoS Attacks?

Obviously having more vCPU's (virtual CPU's) and more RAM by them self won't be able to alone help stop and/or prevent a DDoS attack, but let's say after a DDoS attack is finished and/or slowing down ...
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Performance on Pinned CPU cores versus automatically managed?

I have a XenServer 7.5 environment where I'm running a single Windows VM with 16 total vCPU's. My server has dual Xeon E5-2620v4 CPU's with 8cores/16threads each clocked at 2.1GHz nominal and a Max ...
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3 votes
2 answers
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Can the number of CPU cores be reduced for a CentOS virtual machine?

Our VMware admins tell me that we can add additional virtual CPU cores to our VM's, but they tell me that we can't reduce the number of virtual CPU cores. One recently stated, "CPU on the other hand ...
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Maximum number of virtual CPU for Windows 7/10 virtual machine

For a virtual machine running Windows 7/10, is there a maximum number of virtual CPU a hypervisor can assign to it? As hypervisor, consider VMware ESXi 5.5 or 6.0. Andrea
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3 votes
2 answers
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How to project / measure physical host wait with multi-core guests in ESXi

I’ve heard that if you have a guest with N virtual cores under ESXi, the hypervisor waits for N total logical processors on the host to become available simultaneously before delegating work from the ...
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1 vote
1 answer
34 views

Analyze single CPUs activities instead of sum of total CPU for what is usefull for?

I'm building a monitor to track down all Linux /proc data that can be usefull to understand how the server is behaving. Still I cannot understand if I should track every single CPU (and in a virtual ...
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1 vote
1 answer
607 views

Best VMWare Esxi CPU Resource Allocation Policy

We have a machine with an 88-core CPU in our department. Imagine there are 11 researchers who want to use the machine whenever they have to test a new approach. We've made 11 VMs on VMWare ESXI host, ...
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2 answers
2k views

Microsoft Azure threads per core

I am looking at the Pricing guide for Microsoft Azure. https://azure.microsoft.com/en-us/pricing/details/virtual-machines/windows/ How many threads are working in the "F16" "Compute Optimized" ...
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VMWare Physical CPU to vCPU

We have VMWare hosts with 2 cpus each (that are hyperthreading). We freed up some licensing (2 core licenses) for SQL server and want to upgrade from 4 to 6 cores. From my understanding, for SQL ...
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1 answer
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Decreasing CPU allocation to running Guest Windows server

I have Ubuntu 16.04 as host and windows server 2012 as the guest installed using Virtio drivers in KVM. I am able to increase the CPU while guest is running, however I am not able to decrease the CPU'...
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12 votes
1 answer
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KVM Host with 88 physical cores uses only 14 on 64 core Guest

I do have a server with 2 CPUs (22 Cores each plus HT). I created a KVM Guest with 64 allocated cores. When I run a compilation task the virtual machine shows all 64 cores at 100% (at moderate Disk I/...
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2 votes
2 answers
642 views

Configuring a 1-to-1 allocation of virtual processors

I have a question regarding a recommendation for setting up vCPU on a hyper-v virtual server. Documentation for the application states "For best performance, configure a 1-to-1 allocation of virtual ...
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4 votes
1 answer
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Oversubscription vs Over allocation of vCPU resources in vSphere

I'm trying to understand over allocation of vCPU compared to over subscription of vCPU. For the purposes of the question lets assume the host that I will be using has a 16 core Xeon(2.1Ghz). Based ...
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6 votes
3 answers
3k views

VMware / SQL - physical vs logical cores - how many vCPUs to assign when HT is enabled

We have a ESX host: It has 2 CPU x 8 cores each, and HT enabled. So, total 16 physical cores or 32 logical cores. It has a single dedicated SQL VM on it (no other VMs run on this host), and it has ...
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CPU & Memory Reservation in vSphere & Numa concept

by googling/studying vSphere documentation I have found the possibility to use "Reservation" concept in vSphere. What it is not clear to me is : CPU and Memory reservations are configured separately ...
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1 answer
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Does turning off vCPU in Ubuntu 14.04 impact vmware's cpu scheduler?

I have a Ubuntu VMWare VM that was given 6 CPUs, but rarely sees a load above 1. It is running in a vSphere 5.5 cluster. Nowing that VMWare's CPU scheduler has to clear 6 CPUs for processing this VM,...
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3 votes
1 answer
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Calculation of virtual resources

I virtualized a server using VMware ESXi. My virtual machine has 8 vCPU, while the real processor is an Intel Xeon E5-2620 v3 (6 core) @ 2,4 GHz. In order to estimate virtual resources needed for ...
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2 votes
1 answer
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t2.micro instance is always below baseline CPU usage but still consumes CPU credits - why?

I have a t2.micro instance running Ubuntu Linux on ec2 in Ireland, it's running batch jobs and I've tuned them so that the max CPU is pretty low - it never exceeds 10%. The docs say that: When a ...
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-1 votes
1 answer
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How vCPUs are calculated?

Yesterday I contacted my vendor to buy a server, and I asked them how I should calculate the CPU and RAM requirements for my server, given that I want to create multiple virtual servers on it He said ...
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2 votes
3 answers
84 views

How can I keep a third-party cloud provider accountable for guest VM performance?

I support an ERP system for a manufacturer. We're experiencing intermittent application performance issues on our database, hosted on VMware by a third-party cloud provider. (They're a smaller ...
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2 votes
1 answer
3k views

CPU frequency governor for virtualized guest in VMware

CPU frequency governor can scale the CPU frequency up or down in order to save resources. In a physical server usually have sense, but I don't know if this is applicable for a virtual guest running ...
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0 votes
1 answer
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Xen reduce VCPU

I am trying to reduce the number of VCPU on Dom0, but not understanding why its not reducing the number. Log: [2016-02-11 13:43:25 2550] INFO (XendDomainInfo:1977) Set VCPU count on domain Domain-0 ...
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0 votes
0 answers
520 views

XenServer 6.2 VM Performance (SSD, RAID-10, Quad-core)

Greetings everyone :) My configuration is the following: HP C3000 tower enclosure 1st HP Proliant BL460 G1 quad core xeon 2.66GHz 12MB L2 cache, 24GB RAM, BIOS I15 5/2/2011 partnered with HP ...
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1 vote
2 answers
355 views

What does take all the cpu here?

On a small SSD VPS I got 2 GB of RAM and 2 vCPU core (dedicated to my server), virtualized via KVM. So far so good. The server is mainly used for databases (MySQL) and fast network file storage (via ...
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18 votes
3 answers
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Understanding the VMware ESXi limitations of the free Version

I am running an ESXi Vsphere Client Version 6.0.0 but with all the different documentation and changes I have trouble to understand my limitations. From the official documentation I see that my limit ...
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0 answers
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VPS Server shoots to 900% CPU Utilisation for 10 to 15 minutes

I've just taken a VPS Server with Assured 1 core AMD opetron and burstable to 8 cores. RAM is 5 GB Average Usage so far been around 1 Cpu, but at a point of time - when checked through monitoring - ...
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1 vote
2 answers
4k views

Virtualization: vCPU pinning with Hyperthreading Host CPU?

I'm using KVM/libvirt on a Linux server with Core i7-2600 CPU, which has the following CPU topology (1 Socket, 4 Cores, 8 Threads): Physical | Logical ---------+-------- Core 0 | 0, 4 Core 1 | 1, ...
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3 votes
1 answer
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How to assign dedicated vCPUs to specific VM on Proxmox (KVM) or what system could do that?

I'm posting this here, because what I've found about the topic is either outdated, incomplete or not suitable for various reasons. I have wanted for a long time to learn how to map specific vCPUs to ...
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0 votes
2 answers
166 views

CPU core utilization is automatic?

I have a 512MB KVM Debian OS VPS running several game servers and several sql enabled websites. Currently I have 1 vCPU core and it stays around 15% usage. If I were to get an extra vCPU core will ...
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5 votes
1 answer
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AWS EC2 instance hyperthreading

I am currently doing some performance testing of web-apps that we have moved to AWS. One of the things we have noticed is that vCPU performance doesn't seem to be nearly as good as we'd expected. In ...
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-2 votes
1 answer
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KVM vCPU: Creating VPS with more GHz

I was trying to find a suitable answer to my question about if it is possible to create 2 x 3 GHz guest on a host server that has 6 cores running at 2 GHz. As I understood I would have 12 GHz total ...
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1 vote
2 answers
768 views

Single virtual machine in ESXi with all cores assigned

I have this 2 CPU server (2x4 = 8 cores in total) in which I plan to put a single W2012 virtual machine. Is it a good idea to configure 8 vCPU for the VM or should I leave spare cores to relief ...
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2 votes
1 answer
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How can an ESXi have 1 core and 4 sockets?

I know this is in reference to a vCPU, but even so, logically it doesn't make sense to have 4 sockets and a single core. That sounds to me more like you've filled one of the sockets with a single ...
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-1 votes
1 answer
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vSphere CPU/vCPU Performance [duplicate]

This might be a rookie question but if I'm currently on a 4:1 oversubscription of my CPU ressources does that mean that my processors performances are divided(splitted) into 4 lower perf. vCPU? Will a ...
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1 vote
1 answer
1k views

KVM: How to update amount of cores/procs during runtime

How do I increase the amount of cores/cpus of a vm without requiring a reboot.
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3 votes
1 answer
2k views

virsh vcpu_period and vcpu_quota

I have been looking into ways to divide my CPU amongst KVM guests other than by just setting vCPU access limits. I understand the concept of cpu_shares which can be set/displayed with virsh schedinfo, ...
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