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Beyond the cloud: Hyper-V and Dynamic Memory “under the hood”
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PRC301 Beyond the cloud: Hyper-V and Dynamic Memory “under the hood” Bryon Surace Senior Program Manager Windows Server, Hyper-V Microsoft
description
PRC301. Beyond the cloud: Hyper-V and Dynamic Memory “under the hood”. Bryon Surace Senior Program Manager Windows Server, Hyper-V Microsoft. Agenda. History Hyper-V R2 SP1 Memory & Virtualization Memory Optimization Techniques Hyper-V Dynamic Memory Architecture & Concepts Demo - PowerPoint PPT Presentation
Transcript of Beyond the cloud: Hyper-V and Dynamic Memory “under the hood”
PRC301
Beyond the cloud:Hyper-V and Dynamic Memory “under the hood”
Bryon SuraceSenior Program ManagerWindows Server, Hyper-VMicrosoft
Agenda
History Hyper-V R2 SP1Memory & Virtualization Memory Optimization TechniquesHyper-V Dynamic Memory
Architecture & ConceptsDemoSystem Impact
Q&A
Microsoft Virtualization - Continuing to Evolve!
2011SP1
HYPER-V R2 SP1:REMOTE FX
RemoteFX ClientsTraditional PC
Requires a local IT Pro.
Consumes ~170W.
Cannot meet certain regulatory reqs.
Vulnerable to hardware failures.
Limited to PC form factors.
Windows Server & RemoteFX
Windows Server & RemoteFX
Manageable from anywhere.
Power footprint is shared (~50W/user).
Helps meet regulatory reqs.
Recoverable from hardware failures.
Enables full range of client form factors.
Aero Glass
Adobe Flash
Microsoft Silverlight
DirectX Apps
Windows Media
Traditional Productivity AppsTraditional PC
Powerful
Flexible
Diverse
Versatile
Portable
MICROSOFTREMOTEFX
Deployment ConsiderationsSimple integration with inbox tools
Server ManagerHyper-V Manager – shows up as a 3D video adapterWMI, Power shell support
Performance and ScaleWill have performance whitepaper, planning and deployment guides before SP1 RTM
MigrationRemoteFX for VDI is targeted at new deployments
New HW requirements require new server deploymentsCan have a mix of RemoteFX enabled and non-RemoteFX VMs on the same serverSupports Live Migration across servers – requires identical GPUs
HYPER-V R2 SP1:VIRTUALIZATION & MEMORY
Virtualization & MemoryHow much memory does a server actually need?
IIS Server?Print server?File server?Branch Cache?Direct Access?
How much will performance be affected if you halved the amount of memory in a VM?
No one wants to size VMs Memory“New virtual machines get 1GB of RAM [no matter what the VM is running]. I only give people more memory if they complain about performance”
“All VMs get 4GB of RAM [I have no idea what is happening with that memory] and no one complains”
“I take the minimum system requirements and add (insert one: 50%, 100%, 150%)”
“A vendor tells me their app needs 4GB of RAM. I do not have the time to test this to find out if it is true or not”
Virtualization & MemoryMemory
Key Factor to the number of running VMsThe most utilized asset in the system, but also a more expensive asset
Statistics on resource utilization of workloads CPU 10%Memory 40%Network I/O <5%Disk I/O <5%
Customer RequirementsMaximum density, without sacrificing performanceMaintain consistent performanceDon’t provide a feature that’s unsuitable for production use
Dynamic Memory GoalsHigher VM consolidation ratios with minimal performance impact
Dependent on:How much variation in memory utilization the workloads haveHow good a job you did of sizing the systems in the first place
Work well for both server and desktop workloadsAdd minimal overhead to the system
Understanding philosophical differencesHost and Guest Collaborate
Understands what guest information to useTrying to get the “best bang for buck” in virtual memory management
Host works in IsolationDoes not trust guest information
Building a “black box” solution
Dynamic Memory, not OvercommitOverloaded Term
Over-subscription vs. Over-committment
No one wants to overcommit their resourceYou don’t overcommit other resources (really – you do not)VMware does not want you to overcommit memory (really)
Dynamic Memory treat memory like we treat CPU resources
Dynamically schedulable resource
MEMORY MANAGEMENT & OPTIMIZATION TECHNIQUES
BallooningHow it works:
Increasing the size of the balloon forces the guest to react to memory pressure by releasing unused pagesDecreasing the size makes more memory available to the guest
VMMemory
Host Computer
BalloonDisk
VM
Host Computer
MemoryBalloon
DiskInflate
Swap Out
Ballloon
Deflate
VM
Host Computer
Memory
Disk
Swap In
Balloon
Deflate
Second Level PagingHow it works:
Paging at the virtualization layer by swapping VMs memory out to disk
Many problems:Swapping Guest Kernel ResourcesDouble PagingDisks are slow
But it always works…
External Page SharingHow it works:
Eliminate redundant copies of memory pages common to more than one virtual machine1. Hash all memory and store it in a table…2. Identify the common hashes and then…3. Perform a bit by bit comparison
ProblemsPage Sharing not dynamicCan take hours to share pagesThe largest benefit are zero pagesDoesn’t work with large pages
HYPER-V R2 SP1DYNAMIC MEMORY ARCHITECTURE & CONCEPTS
System Requirements
Parent Requirements:Windows Server 2008 R2 SP1Microsoft Hyper-V Server 2008 R2 SP1
Guest Requirements:Windows Server 2003, 2008 & 2008 R2
32-bit & 64-bit versionsWindows Vista and Windows 7
Enterprise and Ultimate Editions only32-bit & 64-bit versions
Adding/Removing Memory
Adding MemoryEnlightened fashion
Synthetic Memory Driver (VSP/VSC Pair)No hardware emulationLight weight
Removing MemoryBallooning is more efficient
Messes up task manager in the guest OS
Adding/Removing Memory
Active Memory additionMemory is added immediately when VM needs it
Passive Memory reclamationMemory is not removed when there is no immediate needUnutilized memory is collected every 5 minutes
Startup & Max
Startup: amount of memory to boot VMBIOS does not know about DMGuest OS may not know about DMDefault: 512MB
Max: don’t let the VM above this amountDefault: 64GB
Memory Buffer & Priority
Buffer: How much “free” memory should we try and keep in the VM?
Allows for responsiveness to bursty workloadsCan be used for file cache
“I like to configure my virtual machines so that they have ~20% free memory”Priority: which VM gets the memory first
1-10,000: default is 5,000The higher the priority, the higher the availability
Demo
Dynamic Memory in action
SYSTEM IMPACT
VM Reserve
Changes to Root ReserveHyper-V has always had the concept of a reserve of memory that is kept for the parent partition
Host Reserve - Auto-calculated based on:If the machine SLAT capabilityTotal size of host RAMNUMA architecture
Host Reserve VM Overhead Memory utilized by VMs
Changes to Root Reserve
DM allows VMs to push up against the reserve consistentlyNew behavior to better protect the parent partition from rampaging virtual machines
New registry key in placeAllows you to reserve static memory for the parent partition
May result in less memory being available for VMs
Changes to NUMA management…Wait – what is NUMA?Why do I care?How does this work today?
What is “NUMA”?A traditional computer:
Computer
CPU CPU CPU CPU
BUS
Memory
VM VM VM VM
VM VM VM VM
What is “NUMA”?A NUMA computer:
Computer
CPU CPU CPU CPU
BUS
Memory
VM VM VM VM
VM VM VM VM
Back Channel
Memory
BUS
Node 1 Node 2
Why do I care?VM memory should come from the “local NUMA node”
Computer
CPU CPU CPU CPU
BUS
Memory
VM VM VM VM
VM VM VM VM
Back Channel
Memory
BUS
Node 1 Node 2
Good!
Why do I care?Ideally VM memory should come from the “local NUMA node”
Computer
CPU CPU CPU CPU
BUS
Memory
VM VM VM VM
VM VM VM VM
Back Channel
Memory
BUS
Node 1 Node 2
Bad
How does this work today?Hyper-V tries to get all memory for a virtual machine from a single NUMA nodeWhen it cannot – the virtual machine “spans” NUMA nodesUsers can set preferred NUMA nodes for virtual machines in order to get the best distribution
Changes to NUMA managementDynamic memory can result in more virtual machines spanning NUMA nodes
A virtual machine might start all on one node – but added memory might come from another node
New option to disable NUMA node spanning
Disabling NUMA SpanningMakes the system behave like multiple small computers
Computer
CPU CPU CPU CPU
BUS
Memory
VM VM VM VM
VM VM VM VM
Back Channel
Memory
BUS
Node 1 Node 2
What next?
Try Dynamic Memory out – for both server and desktop environments!
Windows Server 2008 R2 SP1 (Trial)Hyper-V Server 2008 R2 SP1 (Free)
Feedback
Dear attendees!Your feedback is appreciated!In notepad that can be found in attendee’s infopack, you will find a feedback formPlease, rate the session and pass the feedback form to the moderator on exitTo take part in a lottery, please do not forget to mark the feedback form with the number of your badgeThank you!
Questions?
PRC301Bryon Surace
Sr. Program Manager, Windows Server [email protected]
You can ask your questions at Microsoft zone in Hall 17 within an hour after end of this session
