Virtual Machine - Edit Settings - (Disk) Part 3(ii)

In my previous post, I have talked about Virtual Machine Storage Policies.
In this post, we"ll be talking about Different types of disk provisioning:-

There are 3 different types of disk provisioning:- 

• Thin Provision
• Thick Provision: i)Eager Zeroed
•                             ii) Lazy Zeroed

By default, a Virtual Machine is Thick Lazy-Zeroed in case of Block-Level storage. You can change the type of disk provisioning at the time of creating a VM in Block-Level Storage. Now I"ll talk about the three types:-

1. Thin Provisioning:- Allocation and Zeroing of blocks are done on demand upon the first write to block. The file blocks are zeroed out when blocks are allocated. File block allocation will be dynamic i.e non-contiguous. Mostly used in Cloud environments or automated infrastructures where provisioning required will be fastest.  This now defaults in case of Virtual SAN.

2. Thick Provision: i)Eager Zeroed:-  File blocks allocated are allocated and Zeroed at the time of vmdk(Disk) creation. In this blocks will be fully allocated & will have highest chances of contiguous file blocks allocation. It will be taking more time during creation.

3. Thick Provision: ii) Lazy Zeroed:-  Blocks are fully preallocated but blocks are zeroed out when each block is first written to. It will be faster than Thick Provision Eager Zeroed.  Chances will be higher of contiguous file block allocation.

There is a topic of debate when to use Thick Provision Eager Zeroed and When to use Thick Provisioned Lazy Zeroed. There's an interesting topic available Eager thick vs Lazy thick disk performance

Virtual Machine - Edit Settings - (Disk) Part 3(i)

So after writing the series for CPU & Memory. This series will be dedicated to Settings related to vmdk i.e Virtual Machine Disk.

• The first option is the size of the virtual machine which can be in MB, GB or TB.
• Maximum Size is the size of the datastore up to which VM hard disk could expand.

VM Storage Policies in production environments is created for storage tiering if using traditional storage i.e Block-Level Storage, Virtual San or a Virtual Volume.

VM Storage policies can be created & managed from vSphere Web Client. I"ll be writing a series of post for different policies which can be created for Virtual SAN, Virtual Volume & Block level storage.

Virtual Machine - CPU (Reservations, Shares & Limits) Part 1(viii)

As I said, we"ll be covering the CPU - Reservation, Shares & Limits.

The SI Unit for CPU is hertz(Hz), frequency or clock cycles per second that were somewhat limited to the first generation CPUs. Now in the 21st Century, CPU's have larger processing capability with more clock cycles per second thereby measured in MHz(MegaHertz) i.e one million cycles per second & GHz(GigaHertz) i.e one billion cycles per second.

RESERVATION: Guaranteed minimum allocation of Resources.

LIMIT: Upper bound of given resource or the maximum amount of resource CONSUMER is entitled from physical(ESXi). 

SHARES: Priority of a VM's access to a given resource.


In Case of CPU, Share values can be defined as Low, Normal, High & Custom.

In the 2 VMs named, CPU1(Girish01-2), CPU2(Girish01-3). I am running a script to increase the CPU activity.
In other 3 VMs named VM01(Low), VM02(Normal) & VM03(High) running normally with different share values.

                           

People are use to ask is there a performance impact on the VMs!! Nah!. There will be NO IMPACT till the time every one is not hungry for resource as soon as every one is hungry for the resource, there you go!!

As given in the screenshot with the help of CPU shares, the VM01 with high is getting more priority and henceforth.

Reference:Click here.

Virtual Machine - Edit Settings (Memory) Part 2 (i)

In my previous Series of posts, we have explored options available under CPU(Part1 to Part7).
In this series, we are going to talk about Memory options as below:-

As said for CPU & Memory Reservations, Shares & Limits,  I"ll be running a separate post after completing all the options related to virtual machine edit settings.

Here, In this post, the option to explore is Memory Hot Plug.

It can not be enabled when the machine is in running state and as told in case of CPU Hot Add posts earlier, it has to be supported by the operating system as in these given KB2020993 & KB2051989 articles.

Using this option, Memory Hot Plug: Memory can only be increased, it can not be decreased.
Given below is the screenshot of Windows Server 2012, Standard Edition that supports increasing the memory on the fly.


Before:                                 After:

     

Virtual Machine - Edit Settings (CPU) Part 1 (vii)

In my previous post, I have talked about scheduling affinity.
In this post Part 7, I am going to talk about CPU/MMU Virtualization.

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

11. CPU/MMU Virtualization:- By default, it is automatic. Here, we get three options in this drop-down i.e

i) Software CPU & MMU

ii) Hardware CPU, Software MMU

iii) Hardware CPU & MMU

Software CPU - Software Based CPU Virtualization

Hardware CPU - Hardware assisted CPU Virtualization

Hardware MMU(Memory Management Unit) & Software MMU (Memory Management Unit)

For better understanding refer to this article.

Virtual Machine - Edit Settings (CPU) Part 1 (iv)

In my previous post, we have talked about Performance Counter.
In this post CPU Part 6, We are going to talk about Scheduling Affinity

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

10. Scheduling Affinity:-  By default, a virtual CPU is scheduled to run on a logical CPU. Using this feature one can restrict a VM to a dedicated LCPU. 

EX:- Lets say we have ESXi with 8LCPU numbered from 0 to 7.

If we are using Scheduling affinity then it can be specified as 1,2,3,4-6 either way means you can specify dedicated LCPU number or the range of LCPU that can be used.

USE CASE:- For CPU Intensive VM performance testing purpose to check whethere scheduling it to dedicated LCPU enhances its performance or to check VMs throughput and response time when pinning it down to LCPU.

Virtual Machine - Edit Settings (CPU) Part 1 (v)

In my previous post, we have talked about CPUID Mask.
In this post of CPU Part 5, We are going to talk about Performance Counter

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

9. Enable Virtualized CPU performance counters: It is mainly used by developers for debugging software(software profilers) which is going to run in a VM such as vTune, OProfile, CodeAnalyst.

This feature is going to make some additional CPU related performance counters (MSRs-Model Specific Registers) available to the guest OS.

There is a KB2030221, which is related to what CPU Performance counters are exposed to guest OS.

Virtual Machine - Edit Settings (CPU) Part 4(iv)

In my previous post, we have talked about Enable CPU Hot Add.

I am going to skip Reservations, Limit & Shares which will be covered along with calculations in a later post.

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

7.CPUID Mask: By default, VM is set to expose the NX/XD flag to guest.

This feature helps prevent execution of certain type of code.
Ex: Here, I have Windows 7 32-bit installed in which I have Enabled/Disabled this feature.

Default, Expose NX/XD flag to guest.

Later on, I Hide the NX/XD flag from guest (64-bit Windows Server 2012) I get this error.

I tried it on Windows7-32 bit, it has a feature DEP (Data Execution Prevention)

Virtual Machine - Edit Settings (CPU) Part 3 (iii)

In my previous post, I have talked about CORE.

Now in this Part 3, We are going to talk about ENABLE CPU Hot Add.

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

3.ENABLE CPU Hot Add: This feature lets you add or remove CPU resource to a powered ON virtual machine.
It should be supported by the operating system and should be turned on in advance i.e If VM is running then this option is grayed out. In order to turn it, VM should be in POWERED OFF state.

 

This information is from Windows Server 2012 R2 Standard Edition.

Once CPU Hot Add is enabled: 

This information is from Windows Server 2012 R2 Standard Edition.

Now if you want to decrease the number of CPU, that can only be done if VM is powered OFF.

We are able to edit get this CPU option, I have installed Windows Server 2012 R2 Standard Edition. VMware has published these KB articles related to CPU Hot Add Feature: KB2020993, KB2051989 which relates to this feature for various operating systems.

Virtual Machine - Edit Settings (CPU) Part 1 (ii)

In my previous post, I have talked about CPU.

Now in this Part 2, We are going to talk about CORE.

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

CPU Settings:-
2.CORE: Here I have shared an example of single socket , quad core processor.
Initially when VMware released CORES PER SOCKET, it was there to deal with software licensing issue. So as to reduce number of licenses , which were based on SOCKETS.  Further, for performance it is beyond the scope of this blog post which includes: NUMA, vNUMA CPU technologies.

An interesting example is given on this KB:2078069

Virtual Machine - Edit Settings (CPU) Part 1 (i)

In order to learn more, one has to explore more.
In this series of blog post, i"ll be talking about all the options one have for a virtual machine.

This is Part 1 of virtual machines & I"ll be explaining and giving real time examples for all these options which are available for a virtual machine. In the end, we want our virtual machines to be running healthy. Hell Yeah!!

In this screenshot as you can see, I have used vSphere Web Client, Right Click on virtual machine & edit settings.

CPU Settings:-
1.CPU: It depends on your physical processor(Socket & Cores Per Socket) that are present on your server.
As you can see in my case, what my host(ESXi) has, I can that as LCPU to my VM.
If there is no hyperthreading than the total number of LCPU =8 & if it is enabled then the total number of LCPU=16. VCPU(Virtual CPU for VM) is scheduled on LCPU(Logical CPU, part of core).

So, In my case, the maximum number of vCPU that can be assigned to the VM =16.