Zenoss closes record quarter

Zenoss Closes Record Quarter with Over 100 Enterprise Customers, Opens New Development Center in
Austin Texas

Open Source Vendor Establishes Presence in Systems Management Hotbed

Austin,TX & Annapolis,MD - April 21, 2008 -- Zenoss Inc., a leading provider of open source network
and systems management software, propelled by explosive customer growth has expanded their
operations to Austin, Texas through the addition of a new software development center. The Austin
development team collectively comprises over fifty years of experience bringing enterprise-class
systems management software to market. The Zenoss Austin office will be located in the same
building where management software innovator Tivoli was started and since acquired by IBM. Austin
was chosen for its wealth of talent and access to expertise in a market segment estimated by
Gartner Research to grow to $18.1 billion dollars by 2012.

"Over the years Austin has built up an IT management talent pool that's showing its muscle once
again as evidenced by Zenoss' new Austin office and Solarwinds' filing for an IPO," noted
Austin-based IT analyst Michael Coté of RedMonk. "The developers, architects, management, and
marketers here have spent years building up the skills required to grow and maintain IT management
companies. Because IT management solutions address unique and challenging problems for the
companies that use them, it can be difficult to find personnel with the specialized skills to
develop, scale and support them. Luckily, Austin has managed to hold onto the talented people that
can deliver on those needs to the benefit of numerous IT management companies, big and small, new
and old."

Zenoss' need for expansion is fueled by the rapid growth of its commercial customer base which grew
to over 100 in the quarter, including over 25 public companies and three in the Fortune 100.
Recent customers include Disney, Georgia Tech, CleverSafe, Montavista and Instinet, among others.
Beyond commercial success, the company has grown its open source community to over 30,000 members
and 3,500 active deployments. In March, the company released Zenoss for Service Providers, a
solution designed to meet the unique needs of xSPs.  Initial service providers using Zenoss include
OmniPresence, OpSource and SugarCRM.

"Following a banner year in 2007, we opened 2008 by adding 32 new enterprise customers, our most
successful quarter ever," stated Zenoss CEO Bill Karpovich, "Not only have we increased the number
of customers, but bookings have increased by 90% over the prior quarter. We believe that the
market's appetite for affordable yet powerful management products like Zenoss Enterprise will only
continue to grow."

For more information about Zenoss please visit www.zenoss.com

About Zenoss, Inc.

Zenoss Inc. delivers open source IT management solutions to organizations across the globe.
Flagship product Zenoss Core is a complete network monitoring and systems management platform that
discovers networked IT resources, monitors them for performance and availability, and tracks
changes through a configuration management database (CMDB). One of the ten most active projects on
SourceForge.Net, Zenoss software was downloaded over 350,000 times in 2007. Recent product
accolades include Network World's Clear Choice Award, Enterprise Open Source Magazine Readers'
Choice Award, and a nomination for Best Technical Design in the SourceForge 2007 Community Choice
Awards. Zenoss' customers include some of the world's largest corporations as well as Federal and
State government agencies. Zenoss, Inc. is privately held and headquartered in Annapolis, MD.
Download Zenoss Core free here:  http://www.zenoss.com/download/form .

Press Contact:

SSPR
Tony Keller
719.634.8279
tkeller@sspr.com