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Scaling out...

Posted: Tue Oct 06, 2015 10:09 pm
by dsfh2992
So, how many feeds (or simultaneous aircraft) can VRS handle? What is typically the bottleneck? RAM? Processor?

Anyone interested in a shared server to aggregate feeds?

Thanks,
Dan

Re: Scaling out...

Posted: Tue Oct 06, 2015 10:24 pm
by dsfh2992
Sort of along the same lines, can VRS handle multiple feeds coming into the same port?

The aim is not to have to configure a seperate "receiver" for each feeder.

Re: Scaling out...

Posted: Tue Oct 06, 2015 11:39 pm
by T-EGJA1
dsfh2992 wrote: ......... can VRS handle multiple feeds coming into the same port?

The aim is not to have to configure a seperate "receiver" for each feeder.
I would think that could probably achieve this by using sergsero's excellent 'modesmixer2' (http://xdeco.org/?page_id=48) to merge all your feeds into a single output stream to feed VRS

Re: Scaling out...

Posted: Wed Oct 07, 2015 12:41 am
by dsfh2992
Thanks. I will try that.

Re: Scaling out...

Posted: Sun Oct 11, 2015 12:46 am
by agw
VRS is a 32-bit program so it will max out at 2GB of RAM. I've seen VRS running on sites with 30+ feeds using < 5% CPU and ~150MB, although the options screen gets a bit slow to open when there are a lot of receivers. If you have a lot of feeds then the choice of feed format will make a difference, the aircraft list format is more efficient than the rest.

However, you would need to create a receiver for each feeder. If you want just a single feed then modesmixer2 would definitely be the way to go.

There are already aggregating sites out there, the ones I know of are vrs-world, mlat-radar, vrs-russia and vrs-america. They're not run by me though, if you want to join up with one to share your feed you'll need to get in touch with their respective owners.

Re: Scaling out...

Posted: Sun Oct 11, 2015 5:13 am
by dsfh2992
Ok, thanks for the info!

What is the most optimal feed format? How many simultaneous tracked planes have you seen at the high end?

Currently, I have modesmixer2 as the front end, sending one large "Beast" feed back to VRS. (all feeders are connecting to a single TCP port). I tried removing modeSmixer and have everyone connect to a single configured "receiver" on VRS, and VRS did not seem to like that one bit. Is that supposed to work?

Also, why do those other networks not share their traffic info with the general public? It seems most/all of them limit viewing only to "feeders".


--Dan

Re: Scaling out...

Posted: Sun Oct 11, 2015 5:45 am
by agw
The most optimal feed format is currently Aircraft List (JSON). I'm not sure about the highest number of feeds. I'm getting the ADSBHub feed and that's currently maybe around 1000 aircraft at peak times. That isn't causing any issues with VRS, my instance is running on Windows 7 on a Mac Mini and it's usually running at around 10%, maybe a bit more when there's database activity or picture details are getting refreshed. However when you get to 1000 aircraft the web site can get sluggish unless you set options to cut down on the size of the aircraft list, e.g. only showing aircraft that are on the map.

Push receivers will only accept one incoming connection, they'll drop the rest. You'll need to set up a separate receiver for each feeder and then one merged feed to bring them all together. This does have the advantage of being able to accept different formats from each feeder.

Big feeds need to be hosted on public servers, domestic broadband connections generally don't have enough uplink bandwidth. Hosting companies will charge for both the server and the bandwidth that it uses. Limiting feeds to feeders encourages people to share their feed, which in turn helps cushion the repeated blows that the host's wallet is taking :)

Re: Scaling out...

Posted: Sun Oct 11, 2015 9:22 am
by dsfh2992
Ok, gotcha. Makes sense.

So at > 1000 planes, is the slowness due to the size of the list refreshing, or something else? If the list is limited to "show only visible" is that a viable solution to solve the issue?

Another question - can multiple VRS installs read/write from the basestation.sqb file simultaneously, or is it limited to only one? I am assuming it's limited, but just wanted to ask.

Re: Scaling out...

Posted: Sun Oct 11, 2015 8:50 pm
by agw
Yes, limiting it to just visible aircraft should do the trick, unless you zoom out far enough to see all of the aircraft :)

Multiple VRS installs should be alright with reading from the same BaseStation.sqb, as long as they're all on the same machine. SQLite is not good with locking over a network, they advise against it. However if you have multiple VRS installs on a machine then you should only let one of them write to the database, otherwise you'll get duplicate aircraft and flight records.

Re: Scaling out...

Posted: Mon Oct 12, 2015 3:59 am
by dsfh2992
What would you say the difference in CPU required would be between decoding off of a "Beast" feed vs. JSON, assuming a large number of aircraft?

Also, will VRS make use of multiple processors if they are present?

I have a network of feeders that already peaks around 1000 aircraft and am looking to maybe add a feed from "adsbnet".

Sorry for all the questions, but I do have one more: what would happen if you had two instances of VRS and they were each feeding each other? Would that create a "loop" and make things go wonky, or would it work?