Replication



  • Hi,

    I have just setup a storage group with two nodes. One if the master, the other isn’t.

    Replication starts and I can see the files being ftp’d from the master to the other node.

    However, when the copying of any of the images completes, it immediately restarts the copy of the image. Is this normal behaviour?

    Also, when the replication has completed, should I see the images on the node that they were replicated to, without having to import them?

    Thanks.


  • Moderator

    @craig-stephens said in Replication:

    However, when the copying of any of the images completes, it immediately restarts the copy of the image. Is this normal behaviour?

    No this is not normal. Is your storage node the same version of FOG as your master node? Is your storage node a NAS? The FOG replicator makes a call to the storage node over http to confirm the file size to know if the file made it correctly. If this call is unanswered it might restart the replication.

    Also it would be good to know what version of FOG you are running.

    Also, when the replication has completed, should I see the images on the node that they were replicated to, without having to import them?

    This makes me think you are not using a master storage node configuration. Remember fog images have 2 parts one is the raw data files and the other is the database meta data. For a FOG storage node or a nas functioning as a storage node, the database is on the master node. So all storage nodes know right away about the meta data. If the remote storage node is actually a full fog server then you will need to import the metadata into the database of the remote fog server via using the web ui.



  • Hi,

    Thanks george1421. The second storage node was running 1.5.6. As it is still in a test environment, I completely rebuilt it from scratch. All working fine now.

    Yes, the remote storage node is a full FOG server, so I will export / import the metadata.

    Thanks again 🙂


  • Senior Developer

    @craig-stephens Please provide the full replication log you find in /var/log/fog/... on your master server.


  • Moderator

    @craig-stephens said in Replication:

    However, when the copying of any of the images completes, it immediately restarts the copy of the image. Is this normal behaviour?

    No this is not normal. Is your storage node the same version of FOG as your master node? Is your storage node a NAS? The FOG replicator makes a call to the storage node over http to confirm the file size to know if the file made it correctly. If this call is unanswered it might restart the replication.

    Also it would be good to know what version of FOG you are running.

    Also, when the replication has completed, should I see the images on the node that they were replicated to, without having to import them?

    This makes me think you are not using a master storage node configuration. Remember fog images have 2 parts one is the raw data files and the other is the database meta data. For a FOG storage node or a nas functioning as a storage node, the database is on the master node. So all storage nodes know right away about the meta data. If the remote storage node is actually a full fog server then you will need to import the metadata into the database of the remote fog server via using the web ui.


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