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
VMworld 2014 Wrap-Up: The open source side

September 2nd, 2014

As we mentioned last week, VMware used the stage of VMworld 2014 to “remind” its audience how deeply the company is involved in the open source community.
The company took…

Nutanix raises $140 million in Series E funding

September 1st, 2014

Nutanix, provider of web-scale IT infrastructure to medium and large enterprises with its software-driven Virtual Computing Platform, announced to have raised $140 million in a Series E funding over…

VMworld 2014 Wrap-Up: End User Computing Announcements

September 1st, 2014

The first day at VMworld 2014 was all about the new vCloud Air catalog and VMware’s “we are all open source folks” strategy but progressing in the event has also…

VMworld 2014 Wrap-Up: VMware vCloud Air Announcements

September 1st, 2014

Just before the beginning of VMworld 2014 VMware announced the rebranding of its owned and operated public Infrastructure as a Service (IaaS) service vCloud Hybrid Service (vCHS) into the more…

Red Hat’s CTO resigns

August 29th, 2014

On August 27 Red Hat disclosed that Brian Stevens, the company CTO, has resigned after over 12 years of service, an unexpected news that drew open-source community attention on the…

Release: VMware Site Recovery Manager 5.8 and vSphere Data Protection 5.8

August 25th, 2014

Among the announcements made today at the VMworld 2014 in San Francisco, there are two new releases. VMware disclosed the delivery of new version of its Disaster Recovery and Backup…

Release: VMware NSX 6.1

August 25th, 2014

Today at VMworld 2014 VMware showcased version 6.1 of its network virtualization platform: NSX.
Launched last year at VMworld 2013 NSX is the result of Nicira acquisition and now VMware…

VMware announces EVO:RAIL

August 25th, 2014

I’m not a huge fan of converged infrastructure solutions but a lot of companies love the simplicity and the initial agility of such implementations, that has led to the relative…

VMware launches VMware vRealize Suite

August 25th, 2014

First day at VMworld 2014 in San Francisco, if the tradition is respected most of the big news will come out today, a good example is the announcement of the…

VMware announces updates in Executive Responsibilities

August 22nd, 2014

VMware announced an administrative transformation in order to stimulate technology innovation, to boost its focus on customers, and develop operational effectiveness across the organization.

VMware’s president, Carl Eschenbach who joined…

VMware launches VMware vCloud Air Network program

August 21st, 2014

All the major vendors in the cloud computing market are investing in their hybrid cloud programs, VMware is no exception and today has launched the new VMware vCloud Air Network…

Citrix announces XenApp and XenDesktop 7.6

August 21st, 2014

This week Citrix announced the upcoming 7.6 version of its Virtual Desktop Infrastructure (VDI) product XenDesktop and desktop and virtualization product XenApp.
XenApp product returned in version 7.5 since it…

Red Hat introduces RHEL OpenStack Platform evaluation OVA

August 21st, 2014

Red Hat is putting a lot of effort in its OpenStack distribution that reached version 5 in July introducing the Icehouse OpenStack release.
The Raleigh open source giant has just…

VMware acquires CloudVolumes

August 20th, 2014

Application containerization is one of the hot topics of 2014, the idea of abstracting applications from the underlying OSes is intriguing and suggests a more simple and agile way to…

 
Monthly Archive