SOLVED Synology NAS as master node for multicast?

  • Hello,

    We have set up a new virtual Fog server (Trunk 7128 / Ubuntu 14.04) with a Synology NAS as master storage node, all is working great, except multicast, the multicast log says “This is not the master node”.

    What can we do make multicast work with a Synology NAS as master storage node?


  • Thanks for all the suggestions, we tried all the mount scenarios, its like Tom said you cannot NFS share an NFS/CIFS share.

    It would be awesome if Wayne’s idea can be implemented in Fog so everything can be stored on the NAS, so the virtual Fog server disk space will be as small as possible.

    We think the whole community will be very happy with it… at least we will be 🙂


  • @Tom-Elliott said in Synology NAS as master node for multicast?:

    @Wayne-Workman Sort of…

    We still need to tell the drive to “do” preparative tasks so we actually still mount the NFS so we can apply the mbr and resizes per what the image has.

    I wonder if we could FTP those small files like mbr and partition info onto the target host into RAM instead of NFS mounting the images directory? Just for multicast.

  • @Tom-Elliott Oh. Ok. Well if that’s the case then it isn’t possible because you can’t export a directory that is already exported.

  • @Wayne-Workman Sort of…

    We still need to tell the drive to “do” preparative tasks so we actually still mount the NFS so we can apply the mbr and resizes per what the image has.

  • Asking because I am just looking for clarification - with multicast, the /images directory is not mounted on the target hosts, because multicast instead uses udpsender right? So you could in theory mount a remote NAS to a fog server and multicast from it? Am I wrong or right here?

  • Moderator

    In theory (I just haven’t had to do it yet), you can use a bind mount to do what’s needed here.

    The first step would be to create a mount point on your fog server and then connect to NAS either via nfs or iSCSI to the mount point on the fog server. You would do something in the order of

    mkdir /mnt/fognas
    mount -t nfs <nas_ip_addr>:/<nas_nfs_share> /mnt/fognas

    Then create a bind mount between the /mnt/fognas and /images
    mount -o bind /mnt/fognas /images

    (note: you may need to move the images directory before the bind mount will work.) Once its setup. touch a file in the /images directory and confirm it is created on this nas. When that is done, mv the contents of the old /images directory to /mnt/fognas folder. Then review /images on the fog server to confirm all of the files are where they should be.

    The last bit you need to update is the /etc/fstab so this mount and remount work every time.

    <nas_ip_addr>:/<nas_nfs_share> /mnt/fognas nfs rw,hard,intr,rsize=8192,wsize=8192
    /mnt/fognas /images bind bind 0 0

    Understand I have not tested this myself, but what you want to do is possible (in theory). There will be a performance penalty for doing this since the image will need to move from the nas to the fog server and then from the fog server to the target computer. I have no clue on what you can expect (in regards to performance) from this configuration. I’m going to suspect your NAS will be the slowest part of the deployment.

  • @Systeembeheer Using the NAS mounted to the fog server is possible, but not necessarily straight forward. THis is because most NAS’ allow you to NFS or CIFS mount the share. I’m fairly sure there are other methods as well, but the most common, I would think, would be one of the types stated earlier. Most often, I think, people use NAS NFS mounted to their system. However, this setup doesn’t work in FOG’s typical scenario as FOG NFS share’s the images location as well. You cannot NFS share an NFS share. So the other option would be the CIFS/Samba/Windows Network share mounted as your /images location. This, though, I’m not sure, will allow NFS either. It “MAY” work in the case of deploy, but I’m pretty sure it would fail on an Upload tasking. That and it could be potentially slow as you’re networking sending data across two separate network points.

    On one hand, however, I think you could install the FOG GUI and Services on a NAS, though I wouldn’t know where to begin. Most NAS’s use a Linux backend, so if you can install udpcast and the FOG Services (either init.d scripts or systemctl scripts) and configure them to start up with the nas, you may have some preliminary success. Again, the feasibility of such a thing is unknown at least to me.

  • Hi Tom,

    Thanks for your fast reply. If we create a mount point to the NAS will that work?
    We want to keep the virtual Fog server disk space as small as possible.


  • You can’t. Unless you know of a way to ensure the GUI and fog service files to be installed on the NAS, this is not possible.