Virtual Machine Disk

Recommended Virtual Machine Disks maximum size is 6TB.


In today's fast-paced world, the ITS Private Cloud demands more agility and flexibility from its infrastructure. One of the key features of VMware vSphere is the ability to perform Storage vMotions, these allow you to move virtual machine disk files (VMDKs) from one storage location to another without incurring downtime. This capability can greatly enhance the overall management and maintenance of the ITS Private Cloud virtual infrastructure and help our team respond quickly to changing requirements.


However, there is one important factor that can greatly impact the flexibility of Storage vMotions: the size of the virtual machine disk. The larger the virtual machine disk, the more difficult and time-consuming it is to perform a Storage vMotion. This is because the entire disk must be transferred to the new storage location in a single operation. If the disk is too large, the transfer can take an excessively long time and impact the performance of the virtual environment during the transfer.


Based on years of experience, we have come up with a maximum VMDK size of 6TB to keep Storage vMotion performant. This ensures that the Storage vMotion process remains quick and efficient, while minimizing the performance impact on the virtual machine and virtual infrastructure.


In general, keeping virtual machine disks smaller than 6TB is a good practice that can greatly enhance the flexibility of Storage vMotions, ensuring that our virtual infrastructure remains agile and responsive to changing requirements.


To quickly review your virtual machine disk size, execute the following vss-cli command:

vss-cli --columns moref,name,storage_type,'disks[*].capacity_gib' compute vm ls


University of Toronto - Since 1827