Few questions about SYSTEM_DS and IMAGE_DS with CEPH backend


I’m trying to deploy this configuration: IMAGE_DS for “golden images” I would like to be backed up by CEPH pool using HDDs and SYSTEM_DS for VM disks by CEPH pool using SSDs.

According to CEPH documentation (https://docs.ceph.com/docs/master/rbd/rbd-snapshot/#getting-started-with-layering) it is possible to make a clone of image snapshot to different pool and surprisingly! - it is ( see screenshot ).

So the questions.

  1. What SYSTEM_DS in opennebula using CEPH backend is used for?
    Because every image - persistent and non-persistent - is being cloned into IMAGE_DS whatever I put in TM_MAD_CONF or datastore parameters.

  2. Is it possible to force opennebula to use SYSTEM_DS for clones of image snapshots?

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The key of my questions I think is in fact that I would like to use another CEPH pool in SYSTEM_DS, but OpenNebula CEPH driver does not take that fact into account.

Currently the OpenNebula CEPH drivers does not support this configuration.

Thank you for your answer :slight_smile:

I think this feature is nice. The only thing could be done to support it is taking into account SYSTEM_DS pool_name variable while cloning image snapshot.