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ExaCC: Scale VM Cluster Exadata Usable Storage

Overview:

• With multiple VMs per Exadata Infrastructure feature release, you can scale up or down the following resources on the VM cluster:
  • Local storage /u02. Scaling memory requires a rolling restart of the cluster nodes to take effect
  • Memory. Scaling memory requires a rolling restart of the cluster nodes to take effect
  • OCPU. Scaling OPCU is Online
  • Exadata storage. Scaling OPCU is Online
• The minimum recommended size is 2 TB
• Use the following formula to calculate the minimum required ASM storage:
  • For each disk group, for example, DATA, and RECO, note the total size and free size by running the “asmcmd lsdg” command on any node of the VM cluster
  • Calculate the used size as (Total size – Free size) / 3 for each disk group. The /3 is used because the disk groups are triple-mirrored
  • DATA: RECO ratio is:
    • 80:20 if the Local Backups option was NOT selected in the user interface
    • 40:60 if the Local Backups option was selected in the user interface
  • Ensure that the new total size as given in the user interface passes the following conditions:
    • Used size for DATA * 1.15 <= (New Total size * DATA % )
    • Used size for RECO * 1.15 <= (New Total size * RECO % )

In this blog, I’ll demonstrate the steps to scale up the usable Exadata storage using the OCI console.

 

Steps to Scale Up VM Cluster Exadata Usable Storage 

1. Note the current total size and free size by running “asmcmd lsdg” command on any node of the VM cluster.

 

2.  Sign in to your OCI tenancy where your Exadata Database Service on Cloud @ Customer system is deployed

 

3. Navigate to “Oracle Database” > “Oracle Exadata Database Service on Cloud@Customer” > “Exadata VM Clusters“

 

4. Click on your VM Cluster Name

 

5. On the VM cluster details home page, click the “Scale VM Resources” button.

 

 

6. On the “Scale VM Cluster” screen, under the “Configure the Exadata storage” section, specify the usable Exadata storage new size then click the “Save Changes” button. The new size will be distributed based on the DATA: RECO ratio, which is 80:20 in our example.  

 

The cluster state will switch to “UPDATING”, but all resources will be UP on both nodes.

 

You can track scaling progress and activities from the “Work Requests” page under the Resources section in the VM cluster details home page.

 

 

Once scaling is completed, the cluster’s state will be changed back to “AVAILABLE”. Under the “Resource allocation” section, Exadata Storage (TB) will show the new total usable storage.

 

7. Connect to any of the VM clusters and run “asmcmd lsdg” command to check the ASM disk groups’ new size.

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