Extending Compute Resources
The topics in this section describe the compute resources that you can extend and the implications.
Expanding Volumes
You can expand the size of block volumes and boot volumes. You cannot decrease the size.
You have several options to increase the size of your volumes:
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Expand an existing volume in place with online resizing.
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Restore from a volume backup to a larger volume.
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Clone an existing volume to a new, larger volume.
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Expand an existing volume in place with offline resizing. See Offline Resizing of Block Volumes Using the Compute Web UI.
Caution:
Before you resize a boot or block volume, create a backup of the volume.
After a volume has been resized, the first backup of the resized volume will be a full backup.
For step-by-step instructions for managing the Compute service, refer to the section titled Resizing Volumes in the Block Volume Storage chapter in the Oracle Private Cloud Appliance User Guide.
Offline Resizing of Block Volumes Using the Compute Web UI
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 do not need to rescan the disk.
Before you resize a volume, create a full backup of the volume.
Whenever you detach and reattach volumes, there are complexities and risks for both Linux-based and Microsoft Windows-based compute instances. For more information, refer to the section titled Resizing Volumes in the Block Volume Storage chapter in the User Guide.
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 are online and attached to compute instances.
After the volume is provisioned, you need to run commands to rescan the disk so that the operating system identifies the expanded volume size. You run different rescan commands depending on the operating system of the attached compute instance.
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 is 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:
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Linux
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Microsoft Windows
Here are more details about additional VNICs:
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There's a limit to how many VNICs can be attached to a compute instance, and it varies by shape. See Compute Shapes.
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They can be added only after the compute instance is launched.
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They must always be attached to a compute instance and cannot 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.
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They are automatically detached and deleted when you terminate the compute instance.
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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.
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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 step-by-step instructions for managing the VNICs, refer to the section titled Configuring VNICs and IP Addressing in the Networking chapter in the Oracle Private Cloud Appliance User Guide.