Master Node Storage Group



  • This may have been asked before so apologies if the case. What is the effect of changing the Master Node Storage Group i.e. if the Master node is in the default group and you change it to a new group that has less images in it, will this cause a problem? I dont think it would be but need to check in case for some reason it causes it to delete any images that are not part of the same storage group.



  • I see thank you for explaining that.


  • Moderator

    Replication in FOG always happens from a master node to a storage node. If you move a master node from storage group A to storage group B and its still a master in storage group B, all of the storage nodes in group B will get what ever images are held on the master node. If for some reason you take a master node and move it to storage group B as a storage node (instead of master node) that former master node will take any images sent by the master node in storage group B. No files will be deleted from the former master node of storage group A, BUT if there is a image definition on the master node for storage group B that matches, it will overwrite the files that match. That second part is hard to explain.

    Or to say it a different way, if you move a master node between storage groups, no files will be deleted on the moved master node.


  • Senior Developer

    I’ll try to answer as succinctly as I can:

    Changing the Master Storage Node to another Node means, that new master node is what will be handling the replication of images. This means, other nodes within the group will be receiving the images and image layout of the Master node. This means, if an image is missing on the new master node that exists on other nodes within the group, there is potential those files will be deleted as it will be wanting to make all nodes have the same kind of file/layout structure as the Master node of that group.

    When you change a master node, you are effectively telling the system that it must follow a new structure based on your request. If you do not define a master node to a group, one will be attempted to be defaulted using the Lowest ID of the nodes within the same group. (Assuming Lowest ID = the oldest node within that group.)

    Changing the Node’s Group means just that. If you are changing the master node, a new master for the group you’re removing this node from will need to be defined. Simply moving it to the new group will not make it the master of that group. You would need to define that, unless it is going to be the ONLY node within that group. If you want it to be the “master” node of the new group, before you make the move, I would suggest disabling the FOG Services for all nodes within the group you’re moving the node to so you don’t accidentally have replication happening and potentially removing data from the node accidentally.

    Hopefully this helps and makes sense.


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