| Re: [mosquitto-dev] max system memory and mosquitto persistence file size limit |
You're (unsurprisingly) not the first person with such desires :) You may find byte queue limits to be at least a partial fix, which is now implemented in the development branch: https://github.com/eclipse/mosquitto/commit/c6aac741c2c294b5e2b469ee8c05c1aad5c80c59 (and a few before that) There's still no overall knobs on memory, but having the per client queues tracked in byte levels should certainly make it easier for such a knob to be added. Sincerely, Karl Palsson Kiran Pradeep <kiran.happy@xxxxxxxxx> wrote: > I am trying to limit memory consumed by mosquitto( in memory > queue ). The intention here is that, when running on low RAM > devices ( say 512MB ), I would like mosuqitto to consume not > more than half of system memory( so as not to impact the > system). Currently there is no cap on the memory consumed by > mosquitto broker. > > There is a `max_queued_messages` configuration paramter. But > that limits by number of queued messages and not by memory > consumption. > > I assume using linux cgroups, will result in OOM killer > terminating mosquitto broker. > > Is there any modification, I could do to mosquitto broker, so > that I could limit clients (publishing further messaging) by > memory consumed? Kindly suggest. > > Thanks, > Kiran. > > On 12/12/16, Roger Light <roger@xxxxxxxxxx> wrote: > > Hi Kiran, > > > >> 1. Mosquitto *always* maintains *all messages* in memory db. > > > > This is correct for current versions of mosquitto. It is unlikely that > > this will remain true for future versions. > > > >> 2. I would like to limit max memory used by mosquitto. I am planning > >> to do this enabling REAL_WITH_MEMORY_TRACKING in memory_mosq.c, and > >> returning NULL( ignoring errno ) from _mosquitto_*alloc, functions. > >> Any further clients requests to connect / publish will fail. Mosquitto > >> will gracefully continue to run mainloop. But client interactions will > >> be possible only after mosquitto frees some allocated memory with > >> _mosquitto_free ( possibly after a network connectivity restore ). > > > > That's an interesting idea. In principle I can see what you're trying > > to do, in practice I wouldn't want to guarantee that you'll get useful > > behaviour. For example, if the call in mosquitto_main_loop() > > allocating memory for the pollfds variable fails, the broker will > > exit. > > > > Regards, > > > > Roger > > _______________________________________________ > > mosquitto-dev mailing list > > mosquitto-dev@xxxxxxxxxxx > > To change your delivery options, retrieve your password, or unsubscribe from > > this list, visit > > https://dev.eclipse.org/mailman/listinfo/mosquitto-dev > > > _______________________________________________ > mosquitto-dev mailing list > mosquitto-dev@xxxxxxxxxxx > To change your delivery options, retrieve your password, or > unsubscribe from this list, visit > https://dev.eclipse.org/mailman/listinfo/mosquitto-dev
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