We have 4 Node with 2 DC .
We are seeing
Caused by: java.nio.file.FileSystemException: /apps/cassandra/data/commitlog/CommitLog-6-1544453835569.log: Too many open files .
We have increased the ulimit to 24 k.
lsof | grep <processid>
.3.3 million records .
Found ~ .2.5 millions of records are of TCP connection with either Socket connection status as ESTABLISHED/LISTEN . Found that connections are of datasource on 9042 .