Cassandra mmaps SSTables into memory, of which there can be many files (including all their indexes and what not). Typically it'll do so greedily until you run out of RAM. 65k map areas tends to be quite low and can easily be exceeded - you'd likely need very low density nodes to avoid going over 65k, and thus you'd require lots of nodes (making management harder). I'd recommend figuring out a way to up your limits as the first course of action.
raft.so - Cassandra consulting, support, and managed services On Fri, Apr 16, 2021 at 4:29 AM Jai Bheemsen Rao Dhanwada < jaibheem...@gmail.com> wrote: > Hello All, > > The recommended settings for Cassandra suggests to have a higher value for > vm.max_map_count than the default 65530 > > WARN [main] 2021-04-14 19:10:52,528 StartupChecks.java:311 - Maximum >> number of memory map areas per process (vm.max_map_count) 65530 is too >> low, recommended value: 1048575, you can change it with sysctl. > > > However, I am running Cassandra process as a container, where I don't have > access to change the value on Kubernetes worker node and the cassandra pod > runs with less privileges. I would like to understand why Cassandra needs > a higher value of memory map? and is there a way to restrict Cassandra to > not use beyond the default value of 65530. If there is a way please let me > know how to restrict and also any side effects in making that change? > > Thanks in advance >
