Extending Compute Resources

Expanding Volumes 🔗

You can expand the size of block volumes and boot volumes. You can't decrease the size.

You have several options to increase the size of your volumes:

• Expand an existing volume in place with online resizing.

• Restore from a volume backup to a larger volume.

• Clone an existing volume to a new, larger volume.

• Expand an existing volume in place with offline resizing.

After a volume has been resized, the first backup of the resized volume is a full backup.

Offline Resizing of Block Volumes

With offline resizing, you detach the volume from a compute instance before you expand the volume size. After the volume is resized and reattached, you need to extend the partition, but you don't need to rescan the disk.

Whenever you detach and reattach volumes, there are complexities and risks for both Linux-based and Microsoft Windows-based compute instances. For more information.

Rescanning the Disk for a Block Volume or Boot Volume

The Block Volume service lets you expand the size of block volumes and boot volumes while they're online and attached to compute instances.

After the volume is provisioned, you need to run commands to rescan the disk so that the OS recognizes the expanded volume size. You run different rescan commands depending on the OS of the attached compute instance.

For more information, see Resizing Volumes.

Adding Another Network Interface 🔗

You can add additional VNICs to a compute instance. Each additional VNIC can be in a subnet in the same VCN as the primary VNIC, or in a different subnet that's either in the same VCN or a different one.

You might add a VNIC to connect a compute instance to subnets in multiple VCNs. For example, you might set up your own firewall to protect traffic between VCNs, so the compute instance needs to connect to subnets in different VCNs.

Secondary VNICs are supported for these types of compute instances:

• Linux and Oracle Solaris

• Microsoft Windows

Here are more details about additional VNICs:

• There's a limit to how many VNICs can be attached to a compute instance, and it varies by shape. See Compute Shapes.

• VNICs can be added only after the compute instance is launched.

• VNICs must always be attached to a compute instance and can't be moved. The process of creating an additional VNIC automatically attaches it to the compute instance. The process of detaching a secondary VNIC automatically deletes it.

• VNICs are automatically detached and deleted when you delete the compute instance.

• The compute instance's bandwidth is fixed regardless of the number of VNICs attached. You can't specify a bandwidth limit for a particular VNIC on a compute instance.

• Attaching multiple VNICs from the same subnet CIDR block to a compute instance can introduce asymmetric routing, especially on instances using a variant of Linux. If you need this type of configuration, assign multiple private IP addresses to one VNIC, or using policy-based routing.

For more information, see Configuring VNICs.