How to improve disk I/O performances with VMware Workstation

Posted by virtualization.info Staff   |   Monday, November 21st, 2005   |  

Even on a 2 GB RAM workstation (as mine) VMware virtual machines can run slowly. Too slowly sometimes.

This can depend on a large amount of factors but we can reduce the number to 4 critical issues:

  1. Antivirus real-time protection
    You probably run VMware Workstation on your everyday working computer, and you probably want to stay secure running an antivirus software.

    The most useful feature of any AV is the real-time protection, catching and monitoring I/O accesses of every process for suspicious activities.
    This feature can greatly impact on your VMs performances and should be fine-tuned for virtualization.

    So be sure to create an exclusion filter on your real-time protection settings for .vmdk (VMware virtual disk) and .vmem (VMware virtual memory) files. In this way countinous I/O operations on your virtual machines will not be hit by antivirus checking.

    Note: if you plan to run liveCD operating systems (like Knoppix) inside your VMs or simply often use CD images for installing new software, I highly recommend to exclude .iso files too from AV checking.

  2. HostOS disk fragmentation
    A really performance hitter for virtual machines is a fragmented host OS disk.

    VMs virtual disks are very large (4 GBs at minimum on the average) and are created by default as non preallocated. In other words your virtual disk grow as you install more software on the guest OS till reaching your defined disk limit.
    If you use only one physical disk for everyday work and VMs storing, you probably will use space around a growing virtual disk, obliging your host OS to fragment virtual machines more and more.

    So be sure to:

    • Create a dedicated partition for virtual machines only
    • Create guest OSes virtual disks with Allocate all disk space now option
    • Schedule a daily defragmentation for your virtual machines directories (maybe at launch time or during the night)
  3. Memory trimming
    Workstation checks which part of the guest OS virtual memory is not used and allocates it back to the host OS. This permits to have more concurrent virtual machines running but everytime the guest OS asks back for its memory it suffers a performance degradation.

    So, if you have enough free RAM for all planned concurrent VMs, be sure to disable memory trimming for guest OSes adding the following line to the virtual machine configuration (.vmx) file:

    MemTrimRate=0

    Note: Memory trimming can be disabled through GUI since Workstation 6.0.

  4. Page sharing (quoted from VMware documentation)
    VMware uses a page sharing technique to allow guest memory pages with identical contents to be stored as a single copy-on-write page. Page sharing decreases host memory usage, but consumes system resources, potentially including I/O bandwidth.

    You may want to avoid this overhead for guests for which host memory is plentiful and I/O latency is important. To disable page sharing, add the following line to the virtual machine configuration (.vmx) file:

    sched.mem.pshare.enable=FALSE option

These suggestions will work well for every VMware Workstation 5.x and Player 1.x since both share same engine.


Labels: ,

blog comments powered by Disqus


virtualization.info Newest articles
Amazon releases AWS plugin for Microsoft System Center Virtual Machine Manager

October 30th, 2014

Amazon has released the AWS System Manager for Microsoft System Center Virtual Machine Manager (SCVMM). AWS System Manager is an add-in for SCVMM which allows customers to monitor and manager…

Paper: Project VRC: Phase VII – Impact of Microsoft Application Virtualization (App-V) 5.0, Optimizations and Best Practices

October 29th, 2014

Project VRC, an ititiative started by LogIn Consultants and PQR, has released a new Project Virtual Reality Check (VRC) whitepaper titled:”Phase VII – Impact of Microsoft Application Virtualization (App-V) 5.0,…

Release: Update Rollup 4 for Microsoft System Center 2012 R2

October 28th, 2014

Microsoft has released Update Rollup (UR) 4 for its System Center Suite of products. The update rollup can be installed on top of System Center 2012 R2 products and is…

Microsoft announcements from TechEd Europe 2014

October 28th, 2014

This week Microsoft is holding its annual TechEd Europe conference in Barcelona Spain. During the keynote which was held today Microsoft made several announcements. This posts gives an overview of…

Zerto expands technology for use with Hyper-V

October 28th, 2014

Zerto, provider of Zerto Virtual Replication (ZVR) has announced that its product will also support the Hyper-V virtualization platform from Microsoft. Virtual Replication does per VM replication and recovery…

Paper: Windows Server Technical Preview Step-by-Step Guide Storage Quality of Service

October 28th, 2014

Microsoft has released a paper titled:”Windows Server Technical Preview Step-by-Step Guide: Storage Quality of Service“. The paper which contains 16 pages covers a new Windows Server technology which became available…

Paper: VMware vCloud Automation Center 6.1 – Reference Architecture

October 27th, 2014

VMware has released a paper titled: “VMware vCloud Automation Center 6.1 – Reference Architecture“.
The paper which contains 35 pages provide a reference architecture for setting up vCloud Automation Center…

Citrix results for Q3 2014

October 24th, 2014

On October 22, Citrix announced its financial results for the third quarter of fiscal year 2014, ended September 30, 2014.
The revenues for the third quarter were $759 million for…

VMware results for Q3 2014

October 24th, 2014

On October 21, VMware released the financial results for the third quarter of 2014.
The revenues for the third quarter were $1.53 billion for an increase of 18% compared to…

Paper: Reference Architecture – Director and EdgeSight

October 23rd, 2014

Citrix has released a paper titled: “Reference Architecture: Director and EdgeSight“. The paper which contains 32 pages contains a reference architecture for setting up Citrix Director and Citrix Edgesight.
Citrix…

Paper: Cisco UCS C240-M3 Rack Server with NVIDIA GRID GPU cards on Citrix XenServer 6.2 and XenDesktop 7.5

October 21st, 2014

Cisco has released a paper titled: “Cisco UCS C240-M3 Rack Server with NVIDIA GRID GPU cards on Citrix XenServer 6.2 and XenDesktop 7.5“.
The paper which contains 38 pages will…

Microsoft announces updates to its public and private cloud portfolio

October 20th, 2014

Microsoft today announced several upcoming features to both its public Microsoft Azure services, as its private cloud solution based on Windows Server and System Center. CEO Satya Nadella stated that…

OpenStack releases the 10th version of its IaaS platform called Juno

October 20th, 2014

OpenStack, the open source cloud computing project has released its 10th version of its IaaS platform for public, private and hybrid clouds. This version has 342 new features and…

VMware decides to disable TPS in future ESXi releases by default

October 17th, 2014

In a knowledge base article titled: “Security considerations and disallowing inter-Virtual Machine Transparent Page Sharing (2080735)” published on October 16th, VMware states that it will disable the Transparant Page Sharing…

 
Monthly Archive