Virtual Machine Disk

Recommended Virtual Machine Disks maximum size is 6TB.

Virtual Machine Disk Size

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

Virtual Machine Storage Type

The ITS Private Cloud offers two high-availability storage cluster types per domain, providing users with flexibility and control over their virtual machine storage needs.

Available Storage Options

HDD Enterprise SAS Storage
SSD Enterprise SAS Storage

Each domain (FD1, FD2, FD3, and FD4) is configured with at least two storage options, allowing users to choose the best storage solution for their virtual machines based on their IO requirements.

Configuring Storage

Storage type can be set during deployment or updated on existing virtual machines through the ITS Private Cloud Portal or Command Line Interface.

Reviewing Storage Configuration

To quickly review the storage configuration of your virtual machines, execute the following vss-cli command:

vss-cli --columns moref,name,storage_type,provisioned_gb compute vm ls

Updating Storage Configuration

To update the storage configuration of your virtual machines, use the ITS Private Cloud Portal or Command Line Interface.

Important Considerations

When changing the storage type, a storage vMotion is performed, which may impact IO performance. To minimize disruption, we recommend scheduling the change during a least busy time. Additionally, if your workload is IO-intensive, it is recommended to schedule the change during a maintenance window to ensure minimal impact on your operations.