Mark Grennan
6204 Reeves Ct. Oklahoma City, OK 73122 Cell: 405 343-9332 eMail:





A position as a Database Administrator or Senior Systems Analyst that utilizes my knowledge and experience plus provides me with challenging responsibilities.





Manage multiple redundant data centers and staff, with Intel based systems utilizing virtual servers to support enterprise Internet and back office infrastructures running Unix and Windows systems. These environments included public facing applications, firewall and intrusion detection management.

Proficient or familiar with a variety of operating systems, Internet services, programming languages, technologies, including but not limited to: enterprise Internet applications, Linux/Unix, application development and design, Java, Perl, C, XHTML, SQL, databases, debugging, reporting and optimization.




Database Administrator
Weather Decision Technologies
January 2010 Now

Data Center Manager
Meridan Data Center
April 2009 January 1010

Data Center Manager
Crossroads Wireless
March 2008 March 2009
Manage the company's Operations / Business Support Systems (OSS BSS) and data mediation in two data centers, one in Oklahoma City and one in Memphis Tennessee, with a team of five employees. Applications included redundant Windows Active Directory and file servers, Apache Open for Business (ofBiz), Zimbra, MySQL, Pentaho, Zamanda, Cacti and Groundworks monitoring systems all running on Dell M1000e blade servers with VMware ESX, Redhat Linux and EMC SANs.
With a small staff these system where built, brought online in both data centers (within 45 days) and below budget.

Beside these management functions, I personally performed DBA and SAN management duties.


Gold Technical Support Specialist
Dell Computers
March 2007 March 2008
Provided complex hardware and software troubleshooting to resolution for Dell customers. This included managing RAID storage, networking and installing VMware, Windows 2003 and Linux operating systems. After diagnosing hardware issues, I managed the ordering, delivery and installation of needed hardware by either the customer or a Dell technician.

Security Administrator / Senior Systems Administrator
Hertz Corporation
April 2000 January 2007
My first position at Hertz was in information security. I maintained the companies Checkpoint firewalls, email systems and audited for employee Internet abuse. Because of my Internet services skills I was invited to work on the companies failing Internet services project.


As senior system administrator, in the Internet Services department, I was responsible for maintaining the public websites and infrastructure. This project had fail to go online for over a year. Within six months of my entering the department it was launched. I directed staff and maintained 22 IBM AIX and 182 Redhat Linux systems. Applications included, Bind DNS, Apache web servers, Websphere application servers, DB2 databases and proprietary load balancing and monitoring systems.


Unix System Administrator
Fleming Companies, Inc.
March 1998 - April 2000
Primary responsibility where managing Fleming's Intranet service called Visionet. I was also responsible for 40+ AIX systems providing accounting and communications services to Fleming's warehouses. I maintained both Websphere and JBoss middleware servers, customer email and account LDAP systems. I also provided on-call support form Cronos time clock systems and wireless communications systems.


Internet Administrator
American Floral Services, Inc
. (Now Teleflora) March 1996 - March 1998
Designed and managed the development of the company's public web site with a team of three employees and one contractor. It was a Java based application using a Netdynamics application server and an Oracle database to provide a complete online catalog.


Applications Specialist / Network Manager
Oklahoma Office of State Finance   
1986 - March 1996
Provided application development and support to other state agencies and I managed the State's wide area network.  As an Application Specialist I was also responsible for the design and development of applications used by the Department of Corrections, Office of State Finance, Oklahoma Horse Racing Commission, the Oklahoma Department of Labor, the Oklahoma Ethics Commission and the Governor's Office.

As Network Manager, I was responsible for installing and managing backbone routers used to provide interagency networks which connected Ethernet, Token Ring, T1 and FDDI services.  I installing and maintaining Novell, Lantastic, StarLan, 3Com, and Corvis networks for other state agencies.

I also designed, installed and maintained the State's first Internet website and eMail systems.



2008 - Brainbench - Linux Administration (Red Hat Enterprise Linux 5)  

2007 - Microsoft Certified Windows XP Professional (70-270)

2007 - Dell PowerEdge blade server components, configuration and troubleshooting

2007 - Brainbench Certified Computer Forensics (U.S.)

2007 - Brainbench Certified Network Security - Transcript ID#: 829201

2006 - Self training OWASP web application security
2003 - IBM WebSphere Developer Training
2002 - IBM WebSphere System Management Training

1998 - General class armature radio license
1996 - NetDynamics Training
1996 - 3Com Router Training
1996 - Lotus Notes Administrator Training




Linux Firewall HOWTO: The Linux Documentation Project - - published February 28, 2000