1GB sounds a little small for that volume, especially if there is any danger of some consumers of durable topics being offline for a while, or of all consumers on a given queue being offline. Either way, you've proven that 1GB isn't enough, by hitting an OOM. The fact that you haven't hit it till now probably means you could get away with using 2GB, but if your host has the memory available, I'm never going to argue against using it.
In your test environment, I'm confused about how you can limit the JVM to 4GB of heap, and then have it take 5GB. Unless the 5GB number is total memory as measured by something like top? If so, that just means that the JVM made the heap 4GB, but it doesn't mean that there's actually 4GB of data in it. Too can't tell you that, so you'd want to use JConsole or JVisualVM to get an understanding of how much heap is actually used and how much time is being spent GCing. Also, can you more clearly describe what you mean by "unresponsive"? Tim On Fri, Apr 6, 2018, 12:22 AM Lionel van den Berg <lion...@gmail.com> wrote: > Hi, > > We're still investigating, turning up logging etc. but we've come across > two issues: > > 1. At our site deployment with default memory usage (1gb) AMQ threw an out > of memory exception. We couldn't determine exactly why, whether it was > cumulative memory use of a peak memory use. We have around 50 connections > and perhaps a few thousand topics with quite a lot of data, perhaps > 4GB/hour going in and 15 x that much going out. > > 2. In our lab we increased memory available to 4Gb by modifying env (see > attached) and turn up logging (also see attached), within about 5 hours AMQ > had reach 5Gb and hung without an exception. Unfortunately the system > wasn't being monitored and apparently the logs weren't any good because > they'd rolled over too many times. > > I realise the information is a little vague at this stage so I'm only > looking for pointers on where to look. >
