Phil Henninge Demand Technology Software 1020 Eighth Avenue South, Suite 6, Naples, FL 34102

Virtual Systems Monitoring and Capacity Planning – An UpdateDemand Technology Software, Inc.

Virtual Systems Monitoring and Capacity

Planning – An UpdateDemand Technology Windows Symposium CMG – 12/05/2005

Phil HenningeDemand Technology Software

1020 Eighth Avenue South, Suite 6, Naples, FL 34102phone: (239) 261-8945 fax: (239) 261-5456

e-mail: [email protected]://www.demandtech.com

2© 2001-2005 Demand Technology Software, Inc.Virtual Systems Monitoring and Capacity Planning – An Update

•Cape Coral•Naples

•Charley August 13, 2004


•Cape Coral•Naples

•Wilma - October 24, 2005


Agenda Review What’s New Virtual Machine Timing What Lies Ahead Sessions Available at CMG Questions


Introduction What is a virtual machine?

An abstract machine for which an interpreter exists. Virtual machines are often used in the implementation of portable executors for high-level languages.

- Melinda Varian, Princeton University Java VM SAS Visual Basic for Applications – VBA

A software emulation of a physical computing environment See http://computing-dictionary.thefreedictionary.com e.g., VM/CMS

http://computing-dictionary.thefreedictionary.com/

http://computing-dictionary.thefreedictionary.com/


Physical Hardware

Host Operating System

Virtual System Software

Virtual Machine Operating System and Applications

Virtual Hardware

Guest Virtual Machine

Virtual Machine Operating System and Applications

Virtual Hardware

Guest Virtual Machine

Virtual System Overview


Introduction

Who Are the Major Players? VMWare (wholly owned subsidiary of EMC)

Workstation - powerful virtual machine software for developers and system administrators

GSX Server -enterprise-class virtual infrastructure for departmental server consolidation and streamlining development and testing operations

ESX Server -virtual infrastructure software for partitioning, consolidating and managing systems in mission-critical environments

Microsoft (formerly Connectix). Virtual PC - a software virtualization solution that allows you to run multiple

PC-based operating systems simultaneously on one workstation. Virtual Server Standard Edition – run on one server with up to 4 processors. Virtual Server Enterprise Edition – run on one server with up to 32

processors.


Introduction – VMWare Virtualization


Introduction - Microsoft VirtualizationFrom the bottom of the stack: The host operating system —

Windows Server 2003— manages the host system.

Virtual Server 2005 provides a VM virtualization layer that manages virtual machines, providing the software infrastructure for hardware emulation.

Each virtual machine consists of a set of virtualized devices, the virtual hardware for each virtual machine.


Roles of Virtual Systems in an Enterprise

Consolidate multiple server workloads. Underutilized Servers Disaster Recovery Environmental and TCO (total cost of ownership)

Re-host legacy applications on newer hardware. NT 4.0 W2K Linux under Windows/Windows under Linux

Enterprise software test and development. Technology arose for ISV test and development.

Technology demos.


Performance Monitoring of VSs

At the system level we look at the system resources CPU Utilization Memory Utilization (memory consumption and paging) Disk Utilization Network Utilization (NIC traffic and topology)

At the software level we look at specific objects. Process (what are the VMWare and Microsoft specific processes) Network Interface (what virtual network adapters are defined) Other Performance Objects


Monitoring VMware VMWare object

One instance for each Virtual Machine Virtual Disk (8 Counters)

– Disk operations (R-W-Total) performed by the guest OS Guest Locked Memory Bytes

– The number of bytes of simulated physical memory that is locked by the guest OS

Guest Virtual Physical Memory Bytes – The number of bytes of simulated physical memory in the

virtual machine Percent Guest Physical Memory Touched

– The percentage of simulated physical memory recently used by the guest OS


Monitoring VMware VMWare object (Continuted)

Network Counters (9 Counters) Network Transfers/sec Network Bytes Transferred/sec

Network Transfer Errors/sec Network Packets Sent/sec Network Bytes Sent/sec

Network Send Errors/sec Network Packets Received/sec Network Bytes Received/sec

Network Receive Errors/sec


Monitoring VMware Host OS

Processes Vmnat, vmnetdhcp,vmware,vmware-authd,vmware-vmx

Network Interface Vmware virtual Ethernet adapter VMNet1, .. Adapter VMNet8

VMWare object One instance for each Virtual Machine

Guest OS Processes

VMWareService, VMWareTray, VMWareUser Network Interface

AMD PCNET Family Ethernet Adapter


Monitoring Virtual Server Virtual Processors Object (Virtual PC)

One instance for each Virtual Machine Guest External Interrupts Number of virtual interrupts delivered to guest OS. Host-to-VMM Context Switches Number of context switches between Windows and the

guest (VMM) context. Cumulative Guest Run Time The guest run time represents the number of microseconds the guest processor has run on a host processor. With the default scaling, the graph represents guest run time percentage. VMM Exceptions Number of processor exceptions handled by the VMM.


Monitoring Virtual Server The Virtual Server WMI Class

contains two objects VirtualMachine - CPU, disk, and network usage

counters – an instance for each virtual machine VirtualNetwork - monitor the usage of each

virtual network (must be attached to a physical NIC – an instance for each virtual network

For detailed information on these objects:http://www.microsoft.com/technet/prodtechnol/virtualserver/2005/proddocs/vs_tr_tools_WMI.mspx

http://www.microsoft.com/technet/prodtechnol/virtualserver/2005/proddocs/vs_tr_tools_WMI.mspx

http://www.microsoft.com/technet/prodtechnol/virtualserver/2005/proddocs/vs_tr_tools_WMI.mspx


Monitoring Virtual Server Host OS

Processes Vssrvc (one for each guest machine)

Virtual Processors Object (Virtual PC) One instance for each Virtual Machine

WMI Objects (Virtual Server) VirtualMachine

One instance for each virtual machine VirtualNetwork

One instance for each virtual network


Monitoring Virtual Server Guest OS

Processes (after Virtual Machine Additions) VMSrvc, VMUSrvc, VMPCMap, Interface

Network Interface Virtual Server - Intel 21140-Based PCI Fast Ethernet

Adapter (Generic) Packet Scheduler Miniport Virtual PC – Intel DC21140 PCI Fast Ethernet

Adapter



HALT/Idle Loop Measurement Anomaly When a machine is idle, its operating system will either issue a HALT

instruction or repeatedly execute an idle loop of NOP instructions Idle loop is the default for most server machines Idle loop is a function contained in hal.dll

When a virtual machine executes an idle loop, it is actively executing instructions which run on the host machine’s physical processor. Thus performance tools in the guest machine will show inactivity, while the host machine will appear fully utilized.

Virtual machines running Windows operating systems having the wrong HAL (Hardware Abstraction Layer) installed will make the guest operating system spin in its idle loop, instead of HALTing when there is nothing else to do.



Halt/Idle Anomaly Even when the correct HAL is installed, some guest

operating systems HALT more aggressively than others.

The multiprocessing HAL favors using the Idle loop, instead of HALTing a processor.

VMWare reports that W2K frequently spins, whereas Windows 2003 HALTs whenever it is idle. See AnswerID 1077 in WMWare’s KB:

http://www.vmware.com/support/kb/enduser/std_adp.php?p_faqid=1077


Virtual Systems Sizing

VMWare Planning Tools VMware P2V Assistant

http://www.vmware.com/products/vtools/p2v_features.html

VMWare Virtual Infrastructure Methodology

http://www.vmware.com/pdf/vim_datasheet.pdf


Virtual Systems Sizing Microsoft Planning Tools

Microsoft Virtual Server Migration Toolkit http://www.microsoft.com/

windowsserversystem/virtualserver/overview/vsmtdatasheet.mspx

Solution Accelerator for Consolidating and Migrating LOB Applications

http://www.microsoft.com/technet/itsolutions/techguide/msa/solacc/lobsa/default.mspx


Virtual Systems Sizing Sizing destination servers requires first

understanding the performance of the applications running on the source servers.

The VM Host machine must contain sufficient capacity (Processor, Memory, Disk and Network) to handle the peak loads of guest machines accumulate measurement data over long term periods that

include seasonal peaks compute Peak:Average ratios and understand when peak

periods occur to ensure they do not overlap on the same host compute 90-95th percentiles


Virtual Systems SizingMetric Average or Median, Peak Notes Processor Total percent of processor time. Required to calculate CPU resource allocation

on destination server. Memory Available bytes of memory. This includes the total standby, free, and zero

page lists. Monitor this counter over time and use the lowest number (minimum value in Windows Performance Monitor) to appropriately represent memory consumption under a load. To express this number in MBs, divide it by 1,024. Subtract this number from the installed memory.

Network I /O Total bytes per second for the network interface (all instances).

To determine the need for dedicated or shared network adapter cards on the destination server.

Disk I /O Physical disk reads per second (all instances). I nclude each physical drive used by the operating system.


CPU Capacity The processor requirements of a source server

should not exceed the processor capacity available to a virtual machine on the destination server. Normalize based on MHz

CPU requirements = number of CPUs x CPU speed x CPU utilization

The % Processor Time for all virtual machines running on a destination server should be < 90 % of the available CPU capacity 10% reserved for the host OS and I/O for virtual machine threads.

CPU capacity = number of processors x CPU speed


Memory Capacity The total amount configured for all virtual

machines cannot exceed the size of physical RAMGuest Memory = sizeof(RAM) – Available Bytes (95th percentile)

Every virtual machine requires an additional 32 MB of physical memory

The host operating system requires exclusive use of at least 384 MB of memory.

Host Memory Capacity >384 + (SizeofVM1+32MB)+(SizeofVM2+32MB)+…+(SizeofVMn+32MB)


Disk Capacity The disk must be sized to support

Physical Disk\Transfers/sec for all guests I/Os.

A single drive can sustain 100-200 random I/Os per second. Faster disks with 15,000 RPMs and 6 ms seek

time may be able to do better. See Friedman’s “A simplified approach to

Windows disk tuning” on Tuesday.


Disk CapacityThe following are best practices for performance optimization

on virtual hard disks: Use a hard disk solution that allows fast access, such as a locally-attached

SCSI hard disk, RAID, or SAN. Put each virtual hard disk on a dedicated volume, SCSI hard disk, RAID, or

SAN disk. It is easiest to put virtual hard disks together with their associated virtual machine configuration files on a RAID or SAN because this keeps everything in one place.

Reduce disk fragmentation. As a dynamically expanding virtual hard disk increases in size, it becomes increasingly fragmented. You can defragment the host operating system to make the virtual hard disk more contiguous. If disk performance is important, consider doing this. Fixed size virtual hard disks are allocated a contiguous block of reserved space on the physical hard disk. Therefore, there is no overhead created by the growing disk.

Compact the virtual hard disks to create more physical disk space.


Network Capacity Provide a dedicated network

adapter in the destination server for each network adapter that existed in the source server.

Configure at least one additional network adapter for managing Virtual Server itself and remote access to virtual machine consoles.


Network Capacity Load balance.

You can load-balance virtual machines for networking. To do this, run a mix of network-intensive and non-network-intensive applications on a single physical computer.

Add network adapters. For best performance, you should allocate a physical network adapter

to each virtual machine. Note: Virtual machines cannot take advantage of software-

based network load balancing (NLB) The Virtual Server network driver runs below the network load

balancing driver in the host operating system network stack. This isolates each host & guest operating systems.


Questions?Resources “VM and the VM Community: Past, Present, and Future” Melinda

Varian, Princeton University:http://pucc.princeton.edu/~melinda/25paper.pdf

Microsoft Virtual Serverhttp://www.microsoft.com/windowsserversystem/virtualserver/default.mspxhttp://www.microsoft.com/virtualserver

VMWarehttp://www.vmware.com

Planning Guide for the Virtual Server 2005 Solution http://www.microsoft.com/technet/itsolutions/techguide/msa/solacc/lobsa/lobsaplg.mspx

VMWare Capacity Planninghttp://www.askewview.net/~lxy/VMware/Capacity_Planning.html


What’s New with VMWare ESX Server 3 and VirtualCenter 2

Distributed Availability Services Distributed Resource Scheduling

VMware Workstation 5.5 64-bit Guest Support for AMD64 and EM64T Systems with

VT Support Two-way Virtual SMP (experimental)

VMware Player Enables Anyone to Easily Run, Share or Evaluate Software

in a Virtual Machine on a Windows or Linux PC


What’s New with Microsoft Virtual Server 2005 R2

High Availability Clustering virtual machines across hosts Host clustering support

Greater Scalability 64-bit (x64) host support

Improved Performance Up to 50% drop in CPU utilization

Improved Manageability PXE network boot support

Better Interoperability Linux guest support


Virtual Machine Timing Whitepaper that discusses timing

mechanisms between operating systems and hardware.

Processes within a virtual machine interact with the virtual machine monitor instead of the hardware:http://www.vmware.com/pdf/vmware_timekeeping.pdf

http://www.vmware.com/pdf/vmware_timekeeping.pdf



Virtual Machine Timing Windows keeps track of time by counting timer

interrupts or timer ticks. When the operating system starts up, it reads the current time to the nearest second from the computer's battery-backed (CMOS) real time clock or queries a network time server to obtain a more precise time.

To update the time from that point on, the operating system sets up one of the computer's hardware timekeeping devices to interrupt periodically at a known rate (say, 100-200 times per second).

This is timekeeping mechanism is known either as the periodic interrupt or the quantum in Windows.


Virtual Machine Timing Types of Hardware Timers

PIT - Programmable Interval Timer CMOS RTC - Real Time Clock Local APIC - Advanced Programmable

Interrupt Controller ACPI - Advanced Configuration and Power

Interface or Chipset TSC - Time Stamp Counter HPET - High Precision Event Timer


Virtual Machine Timing Using a hardware interrupt to track time leads to

problems in the guest virtual machine: At the moment a virtual machine should

generate a timer interrupt, it may not actually be running. In fact, the virtual machine may not get a chance to run again until it has accumulated a backlog of many timer interrupts.

Timer interrupts queued up for a single timer device cause a scalability issue as more and more virtual machines are run on the same physical machine.


Virtual Machine Timing What does this mean for Windows analysts?

“Microsoft Windows has an additional time measurement feature accessed through the QueryPerformanceCounter system call. This name is a misnomer, since the call never accesses the CPU's performance counter registers. Instead, it reads one of the timer devices that have a counter, allowing time measurement with a finer granularity than the interrupt-counting system time of day clock.”


Virtual Machine TimingLet’s look at the counter PERF_100NSEC_TIMER

Description - This counter type shows the active time of a component as a percentage of the total elapsed time of the sample interval. It measures time in units of 100 nanoseconds. Counters of this type are designed to measure the activity of one component at a time.

Formula - (N1 - N0) / (D1 - D0) x 100, where the denominator (D) represents the total elapsed time of the sample interval, and the numerator (N) represents the portions of the sample interval during which the monitored components were active.

Example - Processor\ % User Time


Virtual Machine TimingLet’s Look at another counter PERF_PRECISION_100NS_TIMER

Description - This counter type shows a value that consists of two counter values: the count of the elapsed time of the event being monitored, and the "clock" time from a private timer in the same units. It measures time in 100 nanosecond units. This counter type differs from other counter timers in that the clock tick value accompanies the counter value eliminating any possible difference due to latency from the function call. Precision counter types are used when standard system timers are not precise enough for accurate readings.

Formula - Nx - N0 / D1 - D0, where the numerator (N) represents the counter value, and the denominator (D) is the value of the private timer. The private timer has the same frequency as the 100 nanosecond timer.

Example - PhysicalDisk\% Disk Time


Virtual Machine TimingCounter types and example counters in

Windows Server 2003 using timers: PERF_100NSEC_TIMER – Processor\ % User Time PERF_100NSEC_TIMER_INV – Processor\ % Processor Time PERF_AVERAGE_TIMER - PhysicalDisk\ Avg. Disk

sec/Transfer PERF_ELAPSED_TIME - System\System Up Time PERF_PRECISION_100NS_TIMER - PhysicalDisk\% Disk

Time


What Lies Ahead? Hardware enabled virtualization

Intel - VT: Virtualization Technology formerly ‘Vanderpool’ Now shipping in desktops – server support in 2006

AMD - Pacifica – first half of 2006 Software

VMWare – ESX will most likely be modified to support hardware virtualization

Microsoft – “Longhorn Server” will have extensions after it is released

XenSource – Open source consortium targeting VT and Pacifica Virtuozzo – from SWSoft – uses a customized HAL to virtualize OS


Agenda Review What’s New Virtual Machine Timing What Lies Ahead Virtual Machine Sessions at CMG

2005 Questions


Virtual Machine Sessions at CMG

314 Virtualization: Concepts, Applications, and Performance Modeling TUESDAY 9:15 AM - 10:15 AM OSCEOLA 3&4

324 To V or not to V: A Practical Guide to Virtualization TUESDAY 10:30 AM - 12:00 PM OSCEOLA 3&4

334 Measuring Up for Server Virtualization TUESDAY 2:00 PM - 3:00 PM OSCEOLA 3&4

344 Virtual Performance Won’t Do: Capacity Planning for Virtual Systems TUESDAY 3:45 PM - 4:45 PM OSCEOLA 3&4

546 Modeling VMware ESX Performance THURSDAY 3:45 PM - 4:45 PM OSCEOLA 1&2


Questions?Resources Timekeeping in VMware Virtual Machines:

http://www.vmware.com/pdf/vmware_timekeeping.pdf Microsoft Virtual Server:

http://www.microsoft.com/virtualserver

VMWare:http://www.vmware.com

Others: http://www.xensource.com http://www.swsoft.com/en/products/virtuozzo http://www.run-virtual.com http://about-virtualization.com



http://www.microsoft.com/virtualserver

http://www.vmware.com/

http://www.vmware.com/

http://www.xensource.com/

http://www.swsoft.com/en/products/virtuozzo

http://www.swsoft.com/en/products/virtuozzo

http://www.run-virtual.com/

http://about-virtualization.com/

Phil Henninge Demand Technology Software 1020 Eighth Avenue South, Suite 6, Naples, FL 34102

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