Error when executing "create pfile from spfile"
ORA-27077: too many files open


Based on that error I guess you have reached the limit of maximum open files.

You can check the soft and hard limits with ulimit -Sn and ulimit -Hn. Configure it in /etc/security/limits.conf or a seperate file under /etc/security/limits.d/. Check the list of actual open files with lsof -u oracle (if the user running the instance is oracle).