Use QNAP NAS as source to multicast to clients



  • Hi,

    I recently discovered the fog project and while testing I realized how awesome it is and how perfect it could be used in our environment. However, I am not sure if it is really possible to implement the ideas I have.

    In our office we have a NAS which is connected over 10GbE to a 10GbE Switch, and that switch is connected over 1GbE to multiple clients. My idea is that these clients are partitioned in multiple groups, and each group would receive different images, each over a multicast session. The point is that the clients in each group would still be able to receive the images with (theoretically) 1Gb/s if there are for example only 10 groups but an arbitrary number of clients (in practice that wouldn’t be more than 10 per group).

    From my understanding it wouldn’t be enough to just mount a NAS share on the fog server since that fog server itself is only connected over 1GbE and would represent a bottleneck in that situation.
    I assume, and that’s where I am not sure because I haven’t a great understanding in Multicast connections, that I need to run the fog server on the NAS, is this correct? And if so, is it even possible to run a fog server on a QNAP, it’s OS is called QTS 4.2. The OS has it’s own package manager so I guess somehow it has to be possible, but on the other hand I don’t like installing too much stuff I wouldn’t need (like a Web-Interface and such), I was hoping for simpler a way that the fog server on another machine would point the clients to the NAS and somehow directs how the NAS handles the multicast connections to the clients.

    The NAS itself has a 1,7GHz Quad-Core CPU and it’s RAM can be upgraded to 8GB RAM, so I would hope performance wouldn’t suffer that much, and even if we would only be able to get like half the bandwith this would be a nice success.

    I hope you understood the problem I described and thanks for the great project.

    Thanks in advance.


  • Moderator

    @guyincognito said in Use QNAP NAS as source to multicast to clients:

    I don’t think I want to try running the whole fog-server on the nas, I would be too scared if something brakes after updating the NAS-Software for example. A dedicated fog-server seems to be more practicable.

    I agree 100% with this comment.



  • @george1421 I need to reimage the computers at least every friday evening. It should be done very quickly because we need to check if everything is done correctly before we leave for the weekend. This would be especially important if we would use a new tool like fog-server. The clients need to be done on monday morning.

    I don’t think I want to try running the whole fog-server on the nas, I would be too scared if something brakes after updating the NAS-Software for example. A dedicated fog-server seems to be more practicable.


  • Moderator

    @guyincognito said in Use QNAP NAS as source to multicast to clients:

    I would be able to run the fog server on the NAS?

    The easy answer would be maybe, the harder answer would be can your NAS support the software requirements of FOG (apache, php, ftp, nfs, udpcast) to start with. I know with synology you can get pretty close.

    Something just popped into my mind. I remember seeing somewhere someone put a fog server in a docker container. Can you run docker on your NAS? I feel the cpu in your nas would not be able to handle the load very well. Those CPUs are typically 4 core atom processors, or some other low end ARM or x86 processor.


  • Moderator

    @guyincognito Now there is a way to use the qnap as a fog storage node. From this you can capture and deploy unicast images and take advantage of the 10GbE speeds. But you need the fog server to be able to multicast, and the images have to be local to the fog server. IMO it would be easier to upgrade your fog server to 10GbE instead of trying to make the hardware you have fit the need.

    The one thing I didn’t ask was

    1. How often do you need to reimage these blocks of computers? (once a year, week, day, hour?)
    2. How fast do you need them imaging (like between classes in a school)?


  • @george1421 said in Use QNAP NAS as source to multicast to clients:

    In this case you “in theory” could multicast to 2 groups before flooding your 1GbE server uplink.

    With server uplink you mean the uplink to the fog server? Then I see your point now, I either need a fog server connected over 10 GbE, or (for the sake of arguments) I would be able to run the fog server on the NAS? That was what I was trying to find out. I was just hoping that there was some kind of software or tool that would be easier to run on the NAS which would basically just get instructions from the fog server about what files how to multicast over the network. That way the network load would all be on the NAS and not on the server.

    But I guess a dedicated server with a 10GbE uplink that has an iSCSI drive or whatever mounted from the NAS seems to be the best option. Thank you.


  • Moderator

    @guyincognito said in Use QNAP NAS as source to multicast to clients:

    The Switch we are using is already a 24-Port 10GbE Switch, the NAS has a 10GbE card, each multicast group is connected directly to one port, so that while multicasting each port represents one multicast group and over each port only 1Gb/s is transferred. I don’t see how in this network configuration it shouldn’t be possible to deliver 10 files over 10 multicast groups with 1Gb/s per group.

    This statement has me a little confused to what you are saying. I think I read that you have a 10G core switch and then you have remote switches where you have 10 computers connected via a 1GbE link to the remote switch and then the remote switch is connected to your core switch over a 10G link.

    How multicast works (simply), is that the server sends out a block of data and waits for all subscribers to respond, “got it” and then “ready for the next block”. Then the server sends out the next block. The server won’t send out the next block until it has the “ready for next block” from all subscribers.


  • Moderator

    @guyincognito said in Use QNAP NAS as source to multicast to clients:

    If I understand correctly, you are saying that because the clients are only connected with 1GbE, and that is the maximum they can receive, my 10GbE backbone is pretty much useless.

    Exactly, multicast imaging will only go as fast as the slowest computer in the multicast group.

    My idea however was that I have multiple multiplecast groups running simultaneously,

    In this case you “in theory” could multicast to 2 groups before flooding your 1GbE server uplink.



  • First, thank you very much for your quick response.

    I don’t extactly understand what you are saying. If I understand correctly, you are saying that because the clients are only connected with 1GbE, and that is the maximum they can receive, my 10GbE backbone is pretty much useless. My idea however was that I have multiple multiplecast groups running simultaneously, with each group using only 1GbE, the sum of all can be handled by the NAS and the Switch.

    The Switch we are using is already a 24-Port 10GbE Switch, the NAS has a 10GbE card, each multicast group is connected directly to one port, so that while multicasting each port represents one multicast group and over each port only 1Gb/s is transferred. I don’t see how in this network configuration it shouldn’t be possible to deliver 10 files over 10 multicast groups with 1Gb/s per group.

    The NAS itself is configured with 5 1TB SSD’s with RAID-5, reading 10Gb/s and transferring it over the network in a way that each port of the core switch doesn’t demand more than 1Gb/s is already no problem.


  • Moderator

    Now you can move your FOG server to 10G pretty cheaply as long as you have a 10G switch (that is where the expense is). You can pick up a used Mellonex Connect-2 PCIe network adapter for about $30 USD from a used hardware vendor. You can also pickup a use cisco (or compatible) sfp-h10gb-cu5m spf+ cable for about $25 USD. So for about $60 USD you can upgrade your server to 10G speeds. There are better ways to get to 10G speeds with your server, but none are for less than $100 USD.


  • Moderator

    First lets just say that its not practical to run FOG directly on your NAS device. It may be possible to do if you have vendor supplied packages to install apache, php and other open source packages. The value you receive for the amount of effort to get you there is not worth it.

    For a slight side bar into unicast imaging. You can flood a 1GbE network link if you image 2 new out of box systems (i.e. current technology) simultaneously. We are seeing typically imaging times for a 25GB reference image in the 4 minute range. Yes, FOG can move that fast, we are hitting some networking technology limits with new office class systems.

    Now in your case with multicasting. You will receive no additional performance increase if you move your FOG server to a 10G network over what you have today. In a multicast scenario the entire multicast group images at the rate of the slowest computer in the group. Even if you are imaging 6 core computers running with 16GB of ram and a NVMe disk pair in a RAID 0 configuration. The slowest part of that configuration is the 1GbE uplink to your network core switch (on the client side). A multicast is one sender with many listeners. All of the heavy lifting is done on the client in a FOG environment. The FOG server simply moves data from its local disk, to the network port and manages the entire imaging process. So as long as you have 1 target computer on a GbE link having a 10G server link will not help you (that is a squishy statement at best).

    Now if you are talking about 10 unicast images being pushed out at once then a 10G fog server link is what you need. But then I think you will into disk subsystem performance issues that will impact performance over networking.


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