Resizing Virtual Disks in VMware

Managing virtual disk sizes is a common task for VMware administrators. This guide explains how to safely resize virtual disks in your VMware environment.

Why Resize Virtual Disks?

• Increase storage space for growing applications.
• Optimize resource utilization.
• Fix overprovisioned virtual machines.

Methods to Resize Virtual Disks

1️⃣ Using vSphere Client

1. Power off the virtual machine (if necessary).
2. Right-click VM > Edit Settings.
3. Locate the hard disk you wish to resize.
4. Increase the provisioned size (cannot shrink here).
5. Apply changes and power on VM.

2️⃣ Using ESXi Command Line (CLI)

1. Enable SSH access to the ESXi host.
2. Locate the virtual disk file (.vmdk).
3. Use vmkfstools -X [newsize] [diskname.vmdk] to resize.
4. Example: vmkfstools -X 200G myvm.vmdk

3️⃣ Inside Guest OS (Partition Resize)

1. Boot into the guest OS after disk resize.
2. Use OS-level partition manager (e.g. Disk Management in Windows or gparted in Linux).
3. Expand the partition to use new space.

Best Practices

• Always create a snapshot or backup before resizing.
• Monitor storage utilization regularly.
• Avoid shrinking disks to prevent data loss.