Have you set -Xmx32g ? In this case you may get significantly less available memory because of switch to 64-bit references. See http://java-performance.info/over-32g-heap-java/ for details, and set slightly less than 32Gb
Reid Pinchback at "Sun, 5 Apr 2020 00:50:43 +0000" wrote: RP> Surbi: RP> If you aren’t seeing connection activity in DC2, I’d check to see if the operations hitting DC1 are quorum ops instead of local quorum. That RP> still wouldn’t explain DC2 nodes going down, but would at least explain them doing more work than might be on your radar right now. RP> The hint replay being slow to me sounds like you could be fighting GC. RP> You mentioned bumping the DC2 nodes to 32gb. You might have already been doing this, but if not, be sure to be under 32gb, like 31gb. RP> Otherwise you’re using larger object pointers and could actually have less effective ability to allocate memory. RP> As the problem is only happening in DC2, then there has to be a thing that is true in DC2 that isn’t true in DC1. A difference in hardware, a RP> difference in O/S version, a difference in networking config or physical infrastructure, a difference in client-triggered activity, or a RP> difference in how repairs are handled. Somewhere, there is a difference. I’d start with focusing on that. RP> From: Erick Ramirez <erick.rami...@datastax.com> RP> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org> RP> Date: Saturday, April 4, 2020 at 8:28 PM RP> To: "user@cassandra.apache.org" <user@cassandra.apache.org> RP> Subject: Re: OOM only on one datacenter nodes RP> Message from External Sender RP> With a lack of heapdump for you to analyse, my hypothesis is that your DC2 nodes are taking on traffic (from some client somewhere) but you're RP> just not aware of it. The hints replay is just a side-effect of the nodes getting overloaded. RP> To rule out my hypothesis in the first instance, my recommendation is to monitor the incoming connections to the nodes in DC2. If you don't RP> have monitoring in place, you could simply run netstat at regular intervals and go from there. Cheers! RP> GOT QUESTIONS? Apache Cassandra experts from the community and DataStax have answers! Share your expertise on https://community.datastax.com/. -- With best wishes, Alex Ott Principal Architect, DataStax http://datastax.com/ --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org
