I always believe DBA should have strong knowledge and experience in working on Unix flavor operating system. In this regard Red Hat Linux is always my favourite operating system and always enjoy working on this Unix flavor operating system.
By Almighty 's and some efforts of mine I completed Red Hat Certified System Administrator 7 (RHCSA) EXAM(EX200) certification.
Link below for the credential validation:
Red Hat Enterprise Linux(RHEL) version 7 Training from Reputed training institute or Partner network should help in passing this exam. You can always mail me to firstname.lastname@example.org for any assistance.
Enjoy learning Red Hat Linux.