Manage vCenter Disk Space to Maintain Your VM Performance

Among the myriad resources, disk space emerges as a critical factor that directly influences the performance and overall health of VMs. The article offers valuable insights into expanding disk space, ensuring that VMs have the room they need to thrive.


By Zelia / Updated on August 28, 2023

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The significance of disk space management in maintaining VM performance

Disk space management plays a vital role in the performance of virtual machines (VMs). Efficient utilization and management of disk space are crucial for ensuring optimal VM performance. Here are some key reasons why disk space management is important for VM performance:

  • Storage performance: By managing disk space effectively, you can minimize fragmentation and improve overall storage performance.
  • Swap file usage: Proper disk space management ensures that sufficient space is available for swap files, minimizing their impact on performance.
  • Snapshot and backup operations: Regularly monitoring and managing disk space availability is essential to ensure successful snapshot and backup operations without impacting VM performance.


Built-in vCenter tools for monitoring disk space usage

vCenter, VMware's management platform for virtualized environments, provides several built-in tools for monitoring disk space usage in virtual machines. These tools offer insights into disk usage at different levels of granularity, allowing you to effectively manage disk space and ensure optimal performance. Here are some of the key vCenter tools for monitoring disk space usage:

  • vCenter Alarms: These alarms can be configured to send notifications or perform certain actions, helping you stay informed about disk space usage.
  • vSphere Client or HTML5-based vSphere Client: Within the client, you can navigate to the "Storage" section to view detailed information about datastores and their associated VMs.
  • PowerCLI: With PowerCLI, you can write scripts to gather disk space information, generate reports, and automate disk space management tasks across multiple VMs and datastores.
  • vRealize Operations Manager (vROps): vROps can generate reports, dashboards, and alerts specifically focused on disk space, helping you proactively manage and optimize storage resources.

How to increase disk space in vCenter

Whether accommodating growing data demands or optimizing storage allocation, the process of expanding disk space within vCenter is a pivotal skill for maintaining optimal VM performance. Here's a comprehensive guide on how to add disk space to vCenter server appliance:

✽ Increase vCenter disk space via Bash

1. Adjust the disk size within the virtual hardware settings of the VM as illustrated. Locate the VCSA VM, right-click, and choose Edit Settings. Modify disk size in the vSphere Web client.


2. Initiate an SSH session as root on the appliance. Enter "shell" or "shell.set – enabled true" in the prompt to access BASH. Establish an SSH connection to VCSA, logging in as the root user.


3. Execute the "df -hl" command to exhibit the present disk capacities and utilization. The targeted disk for expansion appears as the final entry. Display disk space usage through the DF command in the BASH environment.


4. Execute the subsequent script once the new size is configured:


The script scans and resizes marked drives for expansion. The output will resemble the following.


5. Re-run "df -hl" to validate the successful resizing of the disk. The size increase, illustrated in the output, confirms the expansion by 10GB.


✽ Add disk space to vCenter using Shell

1. Adjust the size of the chosen VMDK by modifying the virtual hardware settings of the VCSA's VM using the vSphere Web client.

2. Access the appliance via SSH, entering as the root user. Execute the subsequent command:

This is the equivalent to execute df -h within the BASH environment. Although this step is optional, it provides insights into disk utilization, even though the output may not be as user-friendly as that obtained through df -h.


3. Proceed by executing the subsequent shell command to extend the VMDK:

Note: The command does not produce any output. To validate the expansion of the VMDK, revisit step 1's command. Alternatively, switch back to BASH and employ df -h for confirmation.

Safeguard your VMs with secure backup and restoration

While disk space plays a pivotal role in shaping virtual machine (VM) responsiveness, it also underscores the need for comprehensive safeguarding mechanisms. By seamlessly integrating AOMEI Cyber Backup, a robust VMware backup software, you can ensure the resilience and recoverability of the vCenter-managed VMs.

AOMEI Cyber Backup seamlessly integrates with VMware vCenter, allowing you to orchestrate the backup and restoration of VMs with remarkable ease. This integration streamlines the process, eliminating complexities and enabling consistent and reliable data protection. At the same time, it also provides the following benefits:

Agentless Backup: Create complete and independent image-level backup for VMware ESXi and Hyper-V VMs.
Support Free ESXi: Support both paid and free versions of VMware ESXi.
Batch VM Backup: Batch backup large numbers of VMs managed by vCenter Server, or multiple VMs on a standalone ESXi host.
Multiple Storage Destinations: Backup to local or network share destinations.
Automated Execution: Create backup schedules to automate virtual machine protection.

AOMEI Cyber Backup supports VMware ESXi 6.0 and later versions. Next, I will demonstrate how to quickly backup VMware virtual machines. You can click the button below to try AOMEI Cyber Backup for a 30-day free trial:

Download Free TrialVMware ESXi & Hyper-V
Secure Download

*You can choose to install this VM backup software on either Windows or Linux system.

1. Bind Devices: Access to AOMEI Cyber Backup web client, navigate to Source Device >> VMware >> + Add VMware Device to Add vCenter or Standalone ESXi host. And then click >> Bind Device.


2. Create Backup Task: Navigate to Backup Task >> + Create New Task, and select VMware ESXi Backup as the Backup Type. Then set Task Name, Device, Target, Schedule, and Cleanup as needed.

Task Name: Change the task name or use the default name with an ordinal.

Device: Batch select large numbers of VMs managed by vCenter Server for centralized backup.

Target: Select to back up to a local path, or to a network path.

Schedule (optional): Perform full, differential, or incremental backup, and automate execution according to the frequency you specified.


✧Cleanup (optional): Automatically delete the old backup copies that exceed the retention period you specified.


3. Start Backup: Click Start Backup and select Add the schedule and start backup now, or Add the schedule only.


4. Restore from backup: When restoring, you can choose to Restore to original location. It allows you to restore entire VM easily and quickly. It saves time to recreate or configure ESXi virtual machines.


You can also Restore to new location to create a new VM in the same or another datastore/host directly from the backup, saving the trouble of re-configuring the new VM.



Efficient vCenter disk space management encompasses performance optimization, real-time monitoring, expansion flexibility, and secure data protection. As the heart of virtualized environments, disk space influences VM performance and overall system stability.

By harnessing vCenter's tools, expanding disk space seamlessly, and implementing robust backup strategies, you can orchestrate a holistic approach that ensures optimal VM performance, adaptability to evolving needs, and the confidence of data security and recovery.

Zelia · Editor
Zelia is an editor from AOMEI Technology.She mainly writes articles about virtual machine. Writing is one of her hobbies and she wants her articles to be seen by more people. In her spare time, she likes to draw and listen to music, and it is a pleasure for her to focus on her own world.