Virtual Machines 

A Virtual Machine (VM) is a portion of a physical machine that is partitioned off through software so that it acts as an independent physical machine. 

You should indicate that you want a VM when you apply for time on Bridges.  

When you have an active Bridges' grant,  use the VM Request form to request a VM.  This form requests information about the software and hardware resources you need for your VM and your reason for requesting a VM. Your request will be evaluated by PSC staff for its suitability.You will be contacted in one business day about your request.


Why use a VM?

If you need a persistent environment you need to use a virtual machine (VM). Examples of a need for a persistent environment are a Web server with a database backend or just a persistent database.

If you can use a Singularity container rather than a VM, you should use the container. You can set up your Singularity container yourself without any intervention by PSC staff. Also, a VM accrues Service Units (SU) the entire time it is set up, whether or not it is being actively used. Because they only exist while you are using them, containers only accrue SUs for the time during which they are executing.

A VM provides you with control over your environment, but you will have access to the computing power, memory capacity  and file spaces of Bridges.

Common uses of VMs include hosting database and web servers.  These servers can be restricted just to you or you can open them up to outside user communities to share your work. You can also connect your database and web servers and other  processing components in a complex workflow.

VMs provide several other benefits. Since the computing power behind the VM is a supercomputer, sufficient resources are available to support multiple users.  Since each VM acts like an independent machine, user security is heightened. No outside users can violate the security of your independent VM. However, you can allow other users to access your VM if you choose. 

A VM can be customized to meet your requirements.  PSC will set up the VM and give you access to your database and web server at a level that matches your requirements.

To discuss whether a VM would be appropriate for your research project send email to


VMs are affected by system downtime, and will not be available during an outage.  Scheduled downtimes are announced in advance.

Data backups

It is your responsiblity to backup any important data to another location outside of the VM. PSC will make infrequent snapshots of VMs for recovery from system failure, but cannot be responsible for managing your data.

Grant expiration

When your grant expires, your VM will be suspended.  You have a 3-month grace period to request via email to that it be reactivated so that you can move data from the VM. Three months after your grant expires, the VM will be removed.  Please notify if you need help moving your data during the grace period.