What is ISO in VMware?

VMware allows virtual machines to connect to CD/DVD drives on the host machine and access their content. An ISO file is a disk image that contains all the data from a CD/DVD. By mounting an ISO in VMware, you can access the files and programs on that disk from within your virtual machine.

What is ISO in VMware?

Benefits of Using ISOs in VMware

Using ISOs in VMware offers several key benefits:

  • Install new operating systems and software easily without needing the physical disks. An ISO contains everything required for installation.
  • Quickly test different OS versions and software without needing multiple CD/DVDs or disks.
  • Save time and resources by using a single centralized ISO library accessed by all VMs rather than physical media.
  • Easy to manage, share and update ISOs as new versions become available. Much faster distribution to VMs.

How to Mount an ISO in VMware

Mounting an ISO to make it accessible by a VM only takes a few clicks:

  1. Open VM Settings: Click the VM in the VMware inventory, then click “Settings”.
  2. Select CD/DVD Drive: Click “CD/DVD drive” in the “Hardware” section.
  3. Choose “Use ISO Image”: Pick whether to connect at power on or connect immediately.
  4. Browse to ISO Location: Select the datacenter and then choose the ISO.
  5. Connect/Disconnect as Needed: Use the buttons to mount/unmount the ISO as required.

Types of ISOs Used in VMware

Some of the most common types of ISO files used are:

  • OS Installers: Such as Windows, Linux and macOS for deploying fresh operating systems.
  • Software and Tools: Applications, utilities, antivirus software etc that need to be installed.
  • Disk Images: Such as database servers, applications and tools with pre-configured settings.
  • Security Tools: Such as password reset disks to help access locked systems.
  • Diagnostic Tools: Bootable tools to troubleshoot system issues.

Benefits Over Physical Media

Using ISO images offers many benefits compared to physical CD/DVD media:

  • No need to carry discs, risk damage/loss. ISO files are more durable.
  • Much faster to copy and distribute ISOs virtually rather than physically.
  • Central library makes it simpler to organize and manage media effectively.
  • Saves time and money using ISOs compared to constantly burning discs.
  • Easy to backup ISOs to aid disaster recovery unlike physical media.
  • Scriptable automation possible for unattended OS/software deployments.

Optimizing Performance When Using ISOs

To ensure optimal performance:

  • Use a High Speed Store: Choose high-performance storage for the ISO datastore e.g. SSD-accelerated.
  • Local Datastore: Placing the ISO datastore on a host local/direct attached storage device reduces latency.
  • Isolate ISO Traffic: Use a separate vSphere standard switch to carry ISO traffic, isolating it from other storage traffic.
  • Line Rate Networking: Configure network links carrying ISO traffic for maximum line rate throughput.
  • Storage DRS Automation: Let VMware automate optimal placement of ISO datastores.

Top Use Cases and Examples

Some top examples of how ISOs are used with VMware:

  • OS Deployment: Mount Windows 10 or Linux distro ISOs to deploy the OS to new VMs at scale.
  • Software Installation: Mount ISOs with Pinehead Payroll or other applications to roll out across the VM estate.
  • Patching Offline VMs: Mount updates/hotfixes offline VMs by attaching ISO during maintenance windows.
  • Security Audits: Attach diagnostic and hacking ISOs like Kali Linux to identify vulnerabilities.
  • Migration Support: Temporarily mount OS installers to help support physical to virtual migrations.

Key Takeaways

  • ISOs allow VMs access to media without needing physical CDs/DVDs.
  • They help efficiently install software, OSs and tools at scale.
  • Centralized libraries make ISOs easy to manage distribute and update.
  • Performance optimization helps avoid bottlenecks when accessing ISOs.
  • Automation accelerates rollout of upgrades/patches using ISO images.


Mounting ISOs enables VMware administrators to simplify management and accelerate deployment of operating systems, tools and applications across the virtual infrastructure. By moving from physical to virtual media, ISOs create a faster, more resilient distribution mechanism to orchestrate VM provisioning.

Frequently Asked Questions

  1. What file formats can be mounted as ISOs in VMware?
    The supported ISO file formats are ISO-9660 and UDF (Universal Disk Format). These contain full optical disc images that are commonly used for OS installation disks and software.

  2. Can I upload ISOs to ESXi hosts directly?
    No, ISOs need to be uploaded to shared datastores on vSAN/vSphere rather than directly to the ESXi host. The VMs themselves access the ISOs from the shared storage.

  3. Is there a size limit for ISOs used in VMware?
    VMware supports mounting ISOs up to 2040 GB (2 TB). This limit allows for most standard ISOs as well as larger disk images to be attached.

  4. How do I optimize reading ISOs?
    Use high speed, low latency storage (e.g. SSD backed), a dedicated adapter and switch to prioritize traffic. Storage DRS helps place assets optimally too.

  5. Can I boot a VM directly from an ISO?
    Yes, VMware tools like vCenter enable booting VMs directly from ISO files stored in the library without needing other media.

  6. Do I need to unmount ISOs after installing software?
    Generally yes, disconnect the ISO after use as they can slow down the VM if left mounted due to periodic access checks by the OS causing contention.

  7. Is there an easiest way to access ISOs?
    Using a template VM with attached ISO and snapshot makes it quickest to roll out common tools and software to other VMs.

  8. How are ISO images different from OVAs?
    OVAs contain entire VMs while ISOs contain optical media disk images to install operating systems, tools or applications.

  9. Can I connect physical CD drives and ISOs at the same time?
    Yes, VMware tools like Workstation and Fusion support simultaneously mapping both physical CD/DVD drives on the host as well as mounting ISO disk images.

  10. Do I need to convert physical discs to ISOs?
    Yes, physical media needs to be ripped/converted into ISO format if the content needs uploading into a VMware library and attaching to virtual machines.

  11. Should I update my ISOs when new versions are available?
    Yes, updating the ISOs helps ensure you have the latest patches, features and security fixes. It ensures optimal guest OS/application functionality.

  12. Where can I download more ISOs to use with VMware?
    Many vendors like Microsoft provide ISOs for their software as free downloads. Open source OS distros like Ubuntu have ISOs too. Also check tools like OSBoxes.org.

  13. Can I automate mounting ISOs to deploy OSs/software at scale?
    Absolutely. VMware APIs help orchestrate automated OS deployments, boot storms and software installations using ISOs for rapid provisioning.

  14. How can I backup or archive my ISO images?
    Treat ISOs like other vSphere files/VMs and backup to object/cloud storage. Or use ISO management tools offering revision histories and retention policies.

  15. Do ISOs offer security advantages over physical media?
    Yes, central control of ISOs reduces risks of misplaced media with sensitive data. Strict access controls are simpler too.

  16. Which VM hardware version needed to mount ISOs?
    The CD/DVD drive needed to mount ISOs is available from hardware v3 onwards. So modern OSs with appropriate device drivers can access ISOs.

  17. Can I access the data on ISO images from my local desktop?
    Yes, CD/DVD management tools enable browsing the contents of an ISO like a normal disk volume and copy files outside of VMs when needed.

  18. Can I boot different OS installations from the same ISO?
    Yes, a single Windows or Linux ISO can be used to boot multiple installations. However each VM still needs its own separate storage for writes.

  19. Is there a limit on concurrent ISO connections?
    This depends on the storage platform used. Generally there are no explicit limits but contention can occur if many VMs read large ISO files simultaneously from the same datastores.

  20. Should I migrate VMs using Hot Add to attach ISOs?
    When reconfiguring CD/DVD drives, using hot add avoids power cycles. But this can fail when VMs have pending commands to their original hardware device location.

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