I'm working as a system administrator since 2007. Prior to that I've been a Linux trainer for 2 years.
I have hands on experience in Virtualization Solutions like VMWare-5.x,6.x, XenServer, KVM, ProxmoxVE.
Operating Systems :
Redhat9, RHEL-3,4,5,6,7
SuSE/SLES-11,12
Debian,
Ubuntu-9,10,11,12,14.04,14.10
FreeBSD, Solaris
and good experience with Windows Servers as well (2008, 2012 R2) etc.