#3 Oracle Solaris OS:

Oracle Solaris OS is one of the leading operating systems used in many large scale applications. The operating system stands out in security, stability, reliability and performance. Developed under the strong leadership qualities of Sun, the operating system uses UNIX as its core and has a long history in enterprise sector.

The Oracle Solaris OS doesn’t come for free, so users have to go for the paid version, which is offers is credited as one of the best operating systems for servers. In the latest release, the Oracle Solaris provides users with features like Predictive Self Healing, which automatically detects and repairs problems, and DTrace, which allows the admin to observe the work of the OS on all levels and optimize it according to needs. Other features like high performance, ZFS file system- which is one of the fastest and most reliable, better encryption and reliable hardware virtualization support.