Increase the size of a persistent disk

Linux Windows

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You can increase the size of your Persistent Disk when your virtual machine (VM) instance requires additional storage space or increased performance limits. You can increase the disk size at any time, whether or not the disk is attached to a running VM.

This page discusses how to increase the size of a Persistent Disk. To increase the size of a Google Cloud Hyperdisk volume, see Modify the settings of a Hyperdisk.

You can only increase, and not decrease, the size of a disk. To decrease the disk size, you must create a new disk with a smaller size. Until you delete the original, larger disk, you are charged for both disks.

When you create a custom Linux image or custom Windows image, you need to manually increase the size of the boot and non-boot disks. If you're using a public image, Compute Engine automatically resizes the boot disks.

Increasing the size of a disk doesn't delete or modify disk data, but as a best practice, before you make any changes to the file system or partitions, always back up your disk by creating a snapshot.

Compute Engine manages the hardware behind persistent disks, so that you can add and resize your disks without handling striping or redundancy.

Important: Public Google Cloud Images don't use MBR partition types and can only have GPT partition types. Imported Disks with MBR partition type can only be increased to 2 TB. partitions beyond 2 TB or changing the partition type from MBR to GPT isn't supported. Images with MBR partitions are not supported by Cloud Customer Care.

Before you begin

• If you haven't already, then set up authentication. Authentication is the process by which your identity is verified for access to Google Cloud services and APIs. To run code or samples from a local development environment, you can authenticate to Compute Engine by selecting one of the following options:
  

  Select the tab for how you plan to use the samples on this page:

  Console

  When you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication.

  gcloud

  1. Install the Google Cloud CLI, then initialize it by running the following command:

     gcloud init

     Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.
  2. Set a default region and zone.

  Terraform

  To use the Terraform samples on this page in a local development environment, install and initialize the gcloud CLI, and then set up Application Default Credentials with your user credentials.

  1. Install the Google Cloud CLI.

  2. To initialize the gcloud CLI, run the following command:

     gcloud init

  3. If you're using a local shell, then create local authentication credentials for your user account:

     gcloud auth application-default login

     You don't need to do this if you're using Cloud Shell.

  For more information, see Set up authentication for a local development environment.

  REST

  To use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI.

  Install the Google Cloud CLI, then initialize it by running the following command:

  gcloud init

  For more information, see Authenticate for using REST in the Google Cloud authentication documentation.

Required roles and permissions

To get the permission that you need to resize a Persistent Disk, ask your administrator to grant you the following IAM roles on the project:

• Compute Instance Admin (v1) (roles/compute.instanceAdmin.v1)
• To connect to a VM that can run as a service account: Service Account User (v1) (roles/iam.serviceAccountUser)

For more information about granting roles, see Manage access to projects, folders, and organizations.

This predefined role contains the compute.disks.update permission, which is required to resize a Persistent Disk.

You might also be able to get this permission with custom roles or other predefined roles.

Increase the size of a disk

To increase the size of a boot or non-boot disk, use the following procedures:

Note: You can resize an Extreme Persistent Disk only once in a 6 hour period.

Console

1. In the Google Cloud console, go to the Disks page.

   Go to Disks

2. In the list of persistent disks in your project, click the name of the disk that you want to resize.

3. On the disk details page, click Edit. You might need to click the More actions menu and then Edit.

4. In the Size field, enter the new size for your disk. Disks with MBR partition tables can only resize up to 2 TB.

5. Click Save to apply your changes to the disk.

The new disk size is displayed in the list of disks.

gcloud

Use the gcloud compute disks resizecommand and specify the --size flag with the new disk size, in gibibytes (GiB).

gcloud compute disks resize DISK_NAME \
    --size DISK_SIZE \
    --zone=ZONE

Replace the following:

• DISK_NAME: the name of the disk that you are resizing.
• DISK_SIZE: the new size, in gibibytes (GiB), for the disk. Disks with MBR partition tables can resize only up to 2 TB.

• ZONE: For zonal Persistent Disk, specify the zone where the disk is located.

  For Regional Persistent Disk, use instead the --region=REGION flag and specify the region where the regional disk is located.

Terraform

Choose one of the following options to resize either zonal disks or Regional Persistent Disk:

Zonal disk

To change the size of a Persistent Disk, you can use the google_compute_disk resource and use the size parameter.

# Using pd-standard because it's the default for Compute Engine

resource "google_compute_disk" "default" {
  name = "disk-data"
  type = "pd-standard"
  zone = "us-west1-a"
  size = "5"
}

If you include the size parameter along with the image or snapshot parameter, the size value must be equal to or greater than the size of the image or snapshot.

If you omit the image and snapshot parameters, you can set the size parameter to less than the existing disk size. If you do this, Terraform destroys the disk and creates a new empty Persistent Disk.

Caution: To prevent Terraform from destroying and re-creating a disk, you can add the lifecycle.prevent_destroy = true setting to the Terraform configuration.

During the re-creation, Terraform doesn't copy over other data that isn't also included in the Terraform configuration, such as labels or snapshot schedules.

Regional Persistent Disk

To change the size of a Regional Persistent Disk, you can use the google_compute_region_disk resource and use the size parameter.

resource "google_compute_region_disk" "regiondisk" {
  name                      = "region-disk-name"
  snapshot                  = google_compute_snapshot.snapdisk.id
  type                      = "pd-ssd"
  region                    = "us-central1"
  physical_block_size_bytes = 4096
  size                      = 11

  replica_zones = ["us-central1-a", "us-central1-f"]
}

If you include the size parameter along with the image or snapshot parameter, the size value must be equal to or greater than the size of the image or snapshot.

If you omit the image and snapshot parameters, you can set the size parameter to less than the existing disk size. If you do this, Terraform destroys the disk and creates a new empty RegionalPersistent Disk.

Caution: To prevent Terraform from destroying and re-creating a disk, you can add the lifecycle.prevent_destroy = true setting to the Terraform configuration.

During the re-creation, Terraform doesn't copy over other data that isn't also included in the Terraform configuration, such as labels or snapshot schedules.

REST

To resize a Persistent Disk, construct a POST request to the compute.disks.resize method.

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/zones/ZONE/disks/DISK_NAME/resize
{
  "sizeGb": "DISK_SIZE"
}

To resize a Regional Persistent Disk, construct a POST request to the compute.regionDisks.resize method.

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/disks/DISK_NAME/resize
{
   "sizeGb": "DISK_SIZE"
}

Replace the following:

• PROJECT_ID: your project ID.
• ZONE: For zonal Persistent Disk: the zone where the disk is located.
• REGION: For Regional Persistent Disk: the region where the disk is located.
• DISK_NAME: the name of the disk to resize.
• DISK_SIZE: the new size, in gibibytes (GiB), for the disk. Disks with MBR partition tables can resize only up to 2 TB.

Resize the file system and partitions

After increasing the size of a disk, you might need to resize its file system and partitions. The following list shows additional information for boot and non-boot disks:

• Boot disk: If you are using a custom Linux image or a custom Windows image, you must manually resize the root partition and file system. For VMs with public images, Compute Engine automatically resizes the root partition and file system after you increase the size of the boot disk and restart the VM.

• Non-boot disk: After increasing the size of the disk, you must extend the file system on the disk to use the added space.

The following example shows how to manually resize the root partition and file system of a boot disk, and how to manually resize the file system of a non-boot data disk with no partition table. This example assumes that the disk is attached using SCSI and was previously formatted and mounted.

If your Persistent Disk was attached using NVMe, see Resize the file system and partitions for example output for NVMe-attached disks.

Linux VMs

1. In the Google Cloud console, go to the VM instances page.

   Go to VM instances

2. Next to the instance that has the new attached disk, click the SSH button. The browser opens a terminal connection to the instance.

3. Use the df and the lsblk commands to list the size of the file system and to find the device names for your disks.

   $ sudo df -Th
   
   Filesystem      Type     Size   Used  Avail  Use%  Mounted on
   /dev/sda1       ext4     9.7G   1.2G   8.5G   12%  /
   /dev/sdb        ext4     250G    60M   250G    1%  /mnt/disks/disk-1
   
   

   $ sudo lsblk
   
   NAME    MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
   sda       8:0    0   20G  0 disk
   └─sda1    8:1    0   10G  0 part /
   sdb       8:16   0  500G  0 disk /mnt/disks/disk-1
   
   

   This example includes the following disks:

   • Boot disk: The /dev/sda1 partition is on a boot disk that has been resized to 20 GB. The partition table and the file system provide only 9.7 GB to the operating system.
   • Non-boot data disk: The /dev/sdb non-boot data disk has no partition table, but the file system on that disk provides only 250 GB to the operating system. The mount directory for this disk is /mnt/disks/disk-1.

   The df command shows that the /dev/sda1 partition is mounted as the root file system, and the /dev/sdb disk is mounted as a non-boot data disk at /mnt/disks/disk-1. Make note of the Type column, which indicates if your disk uses an ext4 or xfs file system.

4. Verify the partition type:

   sudo parted -l
   

   Alternatively, to see information only for a specific disk:

   sudo parted -l /dev/DEVICE_NAME
   

   Look for the field Partition Table. If the value is msdos, then the disk has an MBR partition type. This means the maximum size of such a disk is 2 TB.

5. Resize the root partition and file system on the boot disk. This example assumes the VM image does not support automatic root partitioning and file system resizing.

   1. Resize the root partition by using parted. For example, the following commands expand partition 1 of /dev/sda to the maximum possible size:

      1. Open parted on the /dev/sda partition:

         sudo parted /dev/sda

      2. At the (parted) prompt, enter:

         resizepart

      3. At the Partition number? prompt, enter:

         1

      4. At the Warning: Partition /dev/sda1 is being used. Are you sure you want to continue? prompt, enter:

         Yes

      5. At the End? prompt, enter

         100%

      6. At the (parted) prompt, enter:

         quit

   2. Read the new partition table using partprobe.

      sudo partprobe /dev/sda
      

   3. Extend the file system:

      • If you are using ext4, use the resize2fs command:

        sudo resize2fs /dev/sda1
        

      • If you are using xfs, use the xfs_growfs command:

        sudo xfs_growfs -d /
        

      • If you are using btrfs, use the btrfs command:

        sudo btrfs filesystem resize max /
        

6. Resize the file system on the non-boot data disk.

   • If you are using ext4, use the resize2fs command to extend the file system:

     sudo resize2fs /dev/DEVICE_NAME
     

     Replace DEVICE_NAME with the device name for the disk. In this example, the device name is /dev/sdb.

   • If you are using xfs, use the xfs_growfs command to extend the file system:

     sudo xfs_growfs MOUNT_DIR
     

     Replace MOUNT_DIR with the mount point of the device. You can find the mount point listed in the MOUNTPOINT column in the output of the lsblk command.

   • If you are using btrfs, use the btrfs command to extend the file system:

     sudo btrfs filesystem resize max MOUNT_DIR
     

     Replace MOUNT_DIR with the mount point of the device. You can find the mount point listed in the MOUNTPOINT column in the output of the lsblk command.

7. Use the df command to verify that the file system is extended. For example:

   df -h /dev/sdb
   
   Filesystem  Size  Used  Avail  Use%  Mounted on
   /dev/sdb    493G   70M  492G     1%  /mnt/disks/disk-1
   

Windows VMs

Use the Windows Disk Management utility to resize partitions on a Windows instance.

1. In the Google Cloud console, go to the VM instances page.

   Go to VM instances

2. Next to the instance that has the resized disk, click the RDP button. The browser opens an RDP connection to the instance.

3. Right-click the Windows Start button and select Disk Management to open the Disk Management tool.

   

4. Show the disks partition type by running in Powershell:

   Get-Disk
   

   In the Partition Style column, if the value is MBR then the disk has an MBR partition type. This means the maximum size of such a disk would be 2 TB.

5. Refresh the Disk Management tool so that it recognizes the additional space on your zonal persistent disk. At the top of the Disk Management window, click Action and select Refresh.

   

6. On the disk that you resized, right-click the formatted partition and select Extend Volume.

   

7. Follow the instructions in the Extend Volume Wizard to extend your existing partition to include the extra disk space. If the existing partition is formatted in NTFS, the maximum partition size is limited by its cluster size settings.

8. After you complete the wizard and the volume finishes formatting, check the Status column on the list of attached disks to ensure that the new disk has a Healthy status.

   

You don't need to restart your VM after you complete this process. You can now use the added disk space to store data.

What's next

• Troubleshooting full disks and disk resizing