Check open files limit for the process named redis:

cat /proc/$(ps aux | grep redis | head -n 1 | kazy -x -r "\d+")/limits | kazy -i "open files" -i Limit

Check current number of open files for the process named redis:

sudo ls -l /proc/$(ps aux | grep redis | head -n 1 | kazy -x -r "\d+")/fd | wc -l