Wondering about OnApp: Zero out Disks When Destroying? We can help you.

As part of our Server Virtualization Technologies and Services, we assist our customers with several OnApp queries.

Today, let us see how we zero out disks in OnApp.

OnApp: Zero out Disks When Destroying

Generally, OnApp provides two ways to clean the VS data when we delete or migrate a VS’s disk.

By default, it will format the physical disk space used by a virtual server when that VS’s virtual disk is deleted, or when the VS’s disk is migrated to another data store.

However, we can also choose to zero out a VS’s disk. This will then take effect for operations queued both via the UI and the API.

Make note that, this will have a noticeable impact on deletion time and the load placed on the Data Store whilst disks fill with zeros since it is a more intensive IO operation.

In addition, if we enable thin provisioning at the SAN side for LVM DataStores, we need to enable this option for space reclamation to happen successfully.

Our Support Techs recommend discussing this with the SAN vendor.

Moving ahead, let us see how our Support Techs enable this behavior.

To do so, we log in via SSH to the Control Panel server.

Then we open the following configuration file to edit:

/onapp/interface/config/on_app.yml

We set the wipe_out_disk_on_destroy parameter from false to true:

wipe_out_disk_on_destroy: true

Eventually, we restart the OnApp service:

service onapp restart

Now when we delete the disks we will see something along the lines of the following in the logs:

Running: dd if=/dev/zero of=/dev/onapp-cmd7y65etpxii8/hkct05vbu21fma bs=4M count=256 conv=notrunc oflag=direct

[Need help with the deletion? Feel free to contact us]

Conclusion

In short, we saw how our Support Techs zero out disks in OnApp.