I have migrated to RHEL 7.4 from 6.9 and same application which used to run fine on 6.9 is running into "Too many open files" issue.
ulimits are set to same values across both environments. upon verifying with "lsof" command, I noticed that the same set of file descriptors are being opened by the process under different "tasks". For e.g. a process which required only 4 file descriptors in RHEL 6.9 uses around 350+ in RHEL 7.4
Due to this any process which opens multiple files runs into the "Too many open files" error within few minutes.
Can anyone guide me down the right path for debugging/fixing this problem?