Twitter continues to grow, and its infrastructure is growing along with it. The popular microblogging service recently surpassed 100 million active users, and is once again expanding its data center network to keep pace. This time, Twitter is looking East.

After an extensive search in which it considered multiple East Coast sites, Twitter has settled on Atlanta as the location for its next data center. The company will move servers into an enormous data center operated by QTS (Quality Technology Services) in downtown Atlanta, industry sources say. The 990,000 square foot Metro Technology Center, owned by QTS, in downtown Atlanta is one of the world’s largest data centers.

Data Center Hubs on Both Coasts

In adding infrastructure in Atlanta, Twitter is pursuing an East-West strategy, with server hubs on both coasts. It’s an approach followed by Internet-scale companies like Facebook and Apple, which have each supplemented their California server farms with huge data centers in North Carolina. This East-West approach places infrastructure closer to more users, which Twitter is hoping can improve delivery speed for the more than 230 million Tweets sent daily.

Up until 2010, Twitter used managed hosting services from NTT America, housing its servers in NTT data centers in Silicon Valley and Ashburn, Virginia. In 2010, Twitter announced that it would operate its own data centers, starting with a new facility in Salt Lake City. Earlier this year, the company leased data center space in Sacramento, Calif. with RagingWire Enterprise Solutions. The company apparently continues to maintain colocation space in Salt Lake City, but there are conflicting reports about its usage of its space at C7 Data Centers.

Massive Data Centers

QTS operates 3.1 million square feet of property in 12 data center facilities, which include more than 1.5 million square feet of raised-floor space. The Metro Atlanta site isn’t even its largest facility, as QTS recently opened a 1.3 million square foot property in a former semiconductor plant near Richmond, Virginia.

The huge Atlanta space offers plenty of room for expansion for growing tenants, which is a consideration for Twitter. QTS also offers flexible pricing on power usage, which can be attractive to companies facing rapid growth. The provider’s  PowerBank plan allows large customers to scale their available power up and down as their requirements change.

That allows companies like Twitter to gradually expand their data center space and power costs over time, rather than purchasing a larger amount up front and seeing some of the capacity go unused as it ramps up its operations in the new site. QTS’s huge data center footprints in Atlanta and Richmond give QTS unusual flexibility in how it partitions its data center space for easy expansion within these buildings.

More Growth Ahead

Twitter is clearly preparing for long-term growth in its IT infrastructure. The company reportedly scouted a number of sitesand providers in Ashburn, Virginia, where Twitter has previously had servers through its use of NTT America. Northern Virginia is a historic meeting point for major fiber networks, and home to peering centers that allow companies to connect to a large number of networks from a single data center.

One of the new entrants in the northern Virginia market is RagingWire, which already hosts Twitter’s servers in its Sacramento facility. There’s been speculation in the industry that Twitter could take space in RagingWire’s new East Coast facility once it opens for business. Other companies bringing new data center space online in northern Virginia include DuPont Fabros Technology, Digital Realty Trust, Latisys, CoreSite, Sabey and Equinix, among others.

It’s not clear whether Twitter opted for Atlanta instead of Virginia, or will eventually seek space in both markets. Twitter CEO Dick Costolo recently projected that the company will add another 26 million users by the end of 2011, meaning that there’s likely more data center expansion ahead for Twitter.

Back in December we reported that Twitter had leased data center space in Sacramento, a surprise move that reflected a shift from its previously announced plans to operate a new facility in Salt Lake City. So what happened to the Salt Lake City project? The parties aren’t saying. But it appears that Twitter continues to lease space in Salt Lake City, even as it focuses much of its expansion energy in other places.

Reuters Reports Cites Transition Troubles
Twitter’s Salt Lake City plans are back in the spotlight after a Reuters story reported that the expansion project had “spiraled out of control,” prompting the shift to the Sacramento site at RagingWire Enterprise. Citing unnamed sources, Reuters reported that the new facility built by C7 Data Centers in Bluffdale, Utah was “plagued with everything from leaky roofs to insufficient power capacity.”

Twitter isn’t offering details on its expansion. Citing customer confidentiality, C7 Data Centers won’t even confirm whether Twitter is a customer. But C7 disputes several of the Reuters story’s characterizations of its Bluffdale facility, and says it has experienced no major customer losses.

“We have not had any attrition of customers equaling more than 1 percent per annum, in the last 4 years,” said Wes Swenson, President of C7 Data Centers.

That suggests that despite its deployment in Sacramento, Twitter remains a customer at the C7 facility – and thus is paying for colocation space that apparently is lightly utilized. Reuters says Twitter signed a 4-year lease with a $24 million commitment for the Utah space. Colocation agreements typically provide limited escape clauses for violations of service level agreements (SLAs) such as extended downtime or thermal events, neither of which appears to be applicable in the case of the Bluffdale site.

Twitter: We’re Making Progress
We reached out to Twitter with questions about its data center expansion, but the company’s only response was a brief prepared statement from Michael Abbott, the company’s VP of engineering. “We’ve done more to upgrade our infrastructure in the last six months than we did in the previous 4.5 years,” said Abbott. “Twitter now has the team and infrastructure in place to capitalize on the tremendous interest in Twitter and continue our record growth.”

In a blog post announcing the completion of its migration, Abbott called the project “the most significant engineering challenge in the history of Twitter.” Abbott wrote that the migration involved testing and data replication between two data centers before migrating its production environment to a third, larger data center, which Abbott described as “our final nesting ground.”

Twitter has been managing its infrastructure through a managed hosting agreement with NTT America, which operates data centers in Silicon Valley and Ashburn, Virginia. Under that arrangement, NTT manages the servers, while Twitter deploys the applications. In its expansion, Twitter was moving into rack-ready colocation space in which it would own and deploy the hardware as well as the applications. This is somewhat different from migrations by other marquee names like Google, Yahoo and Facebook, who managed their own hardware in colocation space and then migrated into data centers they built themselves.

Last July Twitter announced plans to move its infrastructure to a  “new, custom-built data center in the Salt Lake City area.” Subsequent reports identified C7 Data Centers as its new provider.

C7 : We’ve Got Connectivity, Power
C7 Data Centers disputes a section of the Reuters report that the Bluffdale facility “lacked key features such as a second fiber network connection, and less than half of the electricity was actually available.”

Swenson says that XO, Qwest and Integra all have connectivity available at the new data center. “There are three 10G connections with each having dual paths into the building,” he said. “More carriers are on the way. This site is the single largest retail multi-tenant colocation site in the state of Utah, and it pays to be a carrier at such sites. C7 allows clients to connect into our redundant multi-carrier and bandwidth network, or they may choose to connect directly with the carrier.”

The site also has 5 megawatts of power capacity, Swenson says, supplied by two 2.5 megawatt transformers and backed by a pair of 2.5 megawatt generators. The Bluffdale site features 12,000 feet of equipment space, and offers high-density hosting  supported by free cooling, a cold aisle containment system and conputer room air conditioners (CRAC’s) with variable frequency drives.

Roof Leaks Seen During Construction
Swenson acknowledges that the facility experienced some roof leaks during its construction phase, when C7 was retrofitting an existing building. This was problematic because customer equipment was present during the construction.

“We are talking about a couple of drips, not a constant leak,” said Swenson. “We quickly had these patched by a professional roofing company while we continued construction. We did have a customer that had located equipment in the data center while it was being worked on, but the small drips did not hit the equipment, nothing was affected, and nothing had to be moved.”

How did the leaks happen? “To maximize ground space for a free cooling system and future generators, it was necessary to place the chilling system on the roof,” Swenson said. “To do so, we had to place a rather robust mezzanine system on the roof. When the mezzanine was installed, welders did not place the correct protection down, and there was some small solder splatter that penetrated the roof with a few very minute pinholes. During construction we had an occasional rainstorm, that would expose very small pinholes.”

Swenson says C7 replaced the roof with a new one, which has had no issues since the data center entered production in December, despite more than 300 inches of snow during the winter. “We have no outages since being commissioned and in production,” he said. “We continue to take orders, and there are many customers in the facility already.”

Will Twitter eventually shift more of its operations to the Salt Lake City facility? None of the parties will say. But Twitter continues to experience strong growth in traffic. The company said yesterday that it is now handling 155 million tweets per day, up from 55 million at this time last year.

Twitter engineer Michael Abbott provided an overview of the migration process, which involved testing and data replication between two data centers before migrating its production environment to a third, larger data center, which Abbott described as “our final nesting ground.”

Abbott didn’t identify the location of the data centers, but the migration presumably involves Twitter’s first company-operated data center site. Twitter has been managing its infrastructure through a managed hosting agreement with NTT America, which operates several data centers in Silicon Valley, and has used Amazon’s cloud computing services to store and deploy images, including profile pictures. But Twitter said last year that it would begin operating its own facilities.

Last July Twitter said that it would open a new data center located in Salt Lake City, but industry sources say that the company instead leased data center space in Sacramento late last year. It’s not clear which Twitter facility is serving as the “final nesting place,” as some traceroutes show Twitter traffic routing to San Jose, Calif.

The migration involved moving 20 terabytes of Tweets between the three sites, Abbott said. “We hope (the expansion) will have a significant impact the service’s success for many years to come,” he wrote. “During this time, the engineers and operations teams moved Twitter’s infrastructure to a new home while making changes to our infrastructure and our organization that will ensure that we can constantly stay abreast of our capacity needs; give users and developers greater reliability; and, allow for new product offerings.”

The GSMA represents the interests of the worldwide mobile communications industry, uniting nearly 800 of the world’s mobile operators in 219 countries, as well as more than 200 companies in the broader mobile ecosystem, including handset makers, software companies, equipment providers, Internet companies, and media and entertainment organisations.

With global mobile data traffic set to increase exponentially in the coming years, there will be a lot of buzz coming out of the conference, and there are already vendor announcements coming out this week.  The MWC11 conference keynotes alone should be extremely interesting – with Microsoft’s Steve Ballmer (lots of Microsoft/Nokia news lately) and Twitter CEO Dick Costolo on Monday, and Google’s Eric Schmidt on Tuesday. There probably won’t be any 6G announcements like Justin Beiber’s during the Superbowl BestBuy commercial, but there is sure to be a lot of talk about LTE and future R&D coming to market soon.

Let’s take a look at the announcements and news from this week:

4G Networks

CNN reported Verizon Wireless is readying a new cellular calling service, tentatively called VoLTE (Voice Over LTE) that offers better sound quality than its current network and is capable of doing video chat. As a new protocol, it would route calls over the Verizon 4G network that started rolling out last December. Placing calls through the 4G network allows Verizon smartphones to enable both calling and Internet use at the same time – something that only their rivals had been able to do previously. On Wednesday, Verizon Wireless announced that they placed a live, IMS-based VoLTE call over its commercial network.

Extreme Networks (EXTR) announced a family of mobile backhaul routers that will enable mobile operators to smoothly transition cell sites to 4G, while maintaining existing 2G/3G investments. The E4G mobile backhaul family will include Cell Site Routers and Cell Site Aggregation routers that deliver advanced 4G features. “Mobile transport and wholesale operators are looking to build networks for the next decade and want future-proof Ethernet backhaul options. With existing deployments in mobile backhaul networks, Extreme Networks E4G product family has the features to address the requirements of additional mobile operators,” said Michael Howard, principal analyst and co-founder for Infonetics Research. E4G products are expected to be available this calendar year.

Ciena (CIEN) announced the expansion of its Carrier Ethernet Service Delivery (CESD) portfolio with the addition of new switching products designed to address LTE backhaul networking requirements. The new platforms will empower service providers to match the demand for data services with speed scalability and resiliency, while reducing network complexity and lowering operating costs. The CESD portfolio additions include the ActivEdge 3930 and 3931 Serivce Delivery Switches for transitioning to high-bandwidth applications, and the ActivEdge 3916 for lower power consumption in an all GigE compact form factor.

Alcatel-Lucent (ALU) announced lightRadio, a breakthrough in mobile and broadband infrastructure that streamlines and radically simplifies mobile networks. The solution was unveiled at a major press launch event in London supported by partners Freescale and HP. lightRadio represents a new architecture where the base station, typically located at the base of each cell site tower, is broken into its components elements and then distributed into both the antenna and throughout a cloud-like network. Ben Verwaayen, CEO of Alcatel-Lucent, said: “lightRadio is a smart solution to a tough set of problems: high energy costs, the explosion of video on mobile, and connecting the unconnected.” Alcatel-Lucent also recently announced an impressive first field trail on land, with the first 100 Gigabit per second (100G) optical network connection linking the cities of Almaty and Taldykurgan with Kazakhtelecom, Kazakhstan’s leading operator.

Oracle Innovation

Oracle (ORCL) is set to demonstrate their recent innovations at Mobile World Congress 2011. Focused on the communications service providers (CSPs) Oracle will demonstrate upgrades to the Oracle Communications Service Delivery product family, Exadata Database Machine and Exalogic Elastic Cloud, the Sun Netra Carrier grade servers, and a Wireless Application Community (WAC) capable NEAS offerings. “At Mobile World Congress, we look forward to showcasing Oracle’s latest innovations and discussing new trends, including how wireless operators can efficiently deliver and monetize next generation networks and applications to maintain their competitive advantage,” said Dan Ford, vice president of product marketing, Oracle Communications.

VMware’s Mobile Virtualization

VMware (VMW) announced that it will showcase mobile virtualization and enterprise hybrid cloud solutions at this year’s GSMA Mobile World Congress. They will be displaying a broad portfolio of handset and cloud-based software that enables service providers/network operators to generate incremental revenue from services independent of the underlying network, device and type of application. In the short term, this will enable operators to generate more revenue with existing mobile networks, while laying the foundation for unified services.

Snapdragon-Powered

Qualcomm Incorporated (QCOM) announced that its Snapdragon processors are enabling the latest and greatest multimedia experiences in today’s commercial mobile devices, including stereoscopic 3D (S3D) entertainment, 1080p 30fps HD video capture and playback, console-quality gaming and full web browsing with Adobe Flash 10. The newest member of the Snapdragon family, the APQ8060 dual-CPU processor, powers the HP TouchPad, which HP introduced Wednesday . The TouchPad’s advanced graphics are powered by Qualcomm’s Adreno 220 GPU. “With more than 75 Snapdragon devices already announced, 150 Snapdragon devices in development and over 100 high end mobile games optimized for our GPU, Qualcomm continues to be a leader in delivering high performance devices to market,” said Raj Talluri, vice president of product management for Qualcomm.

President Obama’s Wireless Plan

On Thursday, President Obama unveiled his plan to provide 4G wireless broadband coverage to 98 percent of Americans, as promised in his State of the Union speech last month. Enabling that plan is the Wireless Innovation and Infrastructure Initiative where the wireless spectrum is nearly doubled, a $5 billion investment ensures rural areas are not left behind, $3 billion of the spectrum proceeds will go to research and development, a public safety wireless network is deployed, and nearly $10 billion of spectrum auction revenue will be devoted to deficit reduction. GigaOm’s Stacey Higginbotham has the complete details, background, and (excellent) analysis.

Color Me Green

Finally – it wouldn’t be a conference without a ‘Green’ theme – Mobile World Congress will also have plenty of information on Green Initiatives in the industry and in place at the conference.

Business briefings, discussions, videos and some live streaming from the event can be seen on Mobile World Live.

Twitter currently manages its infrastructure through a managed hosting agreement with NTT America, which has cited Twitter’s growth as a driver in the expansion of its data center network. In April Twitter announced plans to add a data center of its own to handle the rapid growth of the microblogging service, which has added more than 100 million new users in 2010. The company announced new funding today, which will help buy more servers and data center space.

Opening “Later This Year”?
In July Twitter said that its new facility would be located in Salt Lake City and open “later this year.” With 2010 drawing to a close, we touched base with Twitter spokesman Matt Graves and asked whether the Salt Lake City data center project was on schedule, or whether the expansion had been postponed or shifted to another location. “We’re still not commenting on our data center,” Graves wrote in an email.

That’s consistent with Twitter’s practice with most data center inquiries. But industry sources say the Sacramento site will now be Twitter’s first expansion beyond its current operations at NTT America.

Popular Market for DR
Sacramento is a popular location for data center infrastructure for disaster recovery, as it’s outside the state’s earthquake zone and about a two-hour drive from either the Bay Area and Silicon Valley. Sacramento also offers moderate power pricing from the Sacramento Municipal Utility District (SMUD). The Sacramento market features a cluster of  commercial data centers, as well as some facilities housing infrastructure for California’s state government

In announcing the company’s expansion plans last July, Twitter’s Jean-Paul Cozzatti outlined the benefits of the move. “Having dedicated data centers will give us more capacity to accommodate this growth in users and activity on Twitter,” Cozzatti wrote on the Twitter Engineering blog. “Second, Twitter will have full control over network and systems configuration, with a much larger footprint in a building designed specifically around our unique power and cooling needs.”

How much larger a footprint?  Twitter was seeking several megawatts of power capacity in the short-term, with the possibility of further expansion in the future.

There are several providers in Sacramento with space available, but those requirements align most closely with RagingWire Enterprise Solutions, a colocation provider that operates a 220,000 square foot data center. RagingWire has been in business since 2000, and recently confirmed plans to build a second data center adjacent to its current facility.

There’s also space available at Herakles Data, another long-term player in the Sacramento colo market, which recently had an anchor tenant vacate about 20,000 square feet of space. Among new players, Advanced Data Centers continues to market its Sacramento facility, but doesn’t currently offer any move-in ready finished space, which would be Twitter’s likely preference.

It’s worth noting that Twitter scouted data center locations in multiple markets in the western United States before announcing its expansion plans in Salt Lake City. What’s clear is that Twitter’s growth is likely to make it a player in the data center and managed hosting market for some time to come.

EDITOR’S NOTE: This story was updated from the original version to note that Twitter has now committed to space in Sacramento.

C7 said this week that it has opened a new 65,000 square foot facility in Bluffdale, Utah with 40,000 square feet of available data center space. The company says that 15,000 square feet of the space at its new site has already been sold or reserved. “Several large companies have already signed multi-year agreements to move into the facility including an anchor tenant,” C7 said in a press release.

Twitter Chooses Salt Lake City
C7 Data Centers didn’t name any of its customers, but Twitter is the prime suspect as the mystery anchor tenant. In July, Twitter said it will build its first custom data center in the Salt Lake City market, which will allow the microblogging service to better manage its growth and “unique power and cooling needs.” Local media subsequently identified C7 as Twitter’s data center provider, and have named Twitter as the anchor tenant in Bluffdale.

So is it Twitter? “We’re still not commenting on the specific location or other details about our data center,” said Twitter’s Matt Graves.

Twitter currently manages its infrastructure through a managed hosting agreement with NTT America, which has cited Twitter’s growth as a driver in the expansion of its data center network.

The opening of the new C7 facility doesn’t mean tenants are ready to launch production, only that the space is open and ready for immediate occupancy.The rest of the data center will be built out in phases over the next 18 months in pods of 10,000 square feet. The facility has been built to include 36-inch raised floors, has 10 megawatts of power capacity, and connectivity from three national bandwidth providers.

Growing Data Center Cluster
Twitter is the fourth high-profile data center project to locate in the Salt Lake City area in recent years, following the lead of eBay, Oracle Corp. and the NSA.

C7 Data Centers CEO Nathan Hatch said companies continue to select Utah for colocation and business continuance because of its low operational costs, and low incidence of natural disasters. “C7 continues to attract companies requiring scalable, world-class data center space,” said Hatch. “Providing real value at a competitive price resonates with prospective customers and our installed client base.”

C7′s involvement in the Twitter project was reported by the Salt Lake Tribune. The company was founded as Center 7, but changed its name to C7 after its acquisition of another local provider, TierFour, in early 2009. The company’s customers include Answers.com and the UK2 web hosting group. Along with its colocation, bandwidth and managed service offerings, C7 offers disaster recovery and remote backup services.

State officials said Twitter has not applied for tax incentives, but Gov. Gary Herbert said Twitter’s presence “will further contribute to the development of critical mass in our software and technology economic cluster.” Twitter is the fourth high-profile data center project to locate in the Salt Lake City area in recent years, following the lead of eBay, Oracle Corp. and the NSA.

Twitter currently manages its infrastructure through a managed hosting agreement with NTT America, which has cited Twitter’s growth as a driver in the expansion of its data center network. In April Twitter announced plans to build a data center of its own. On Wednesday it provided additional details on the Twitter Engineering blog.

C7 Data Centers CEO Nathan Hatch has been a frequent contributor to the Industry Perspectives feature at Data Center Knowledge, sharing his insights on reducing power costs, SAS70 audits and PCI compliance.

The construction project marks the next phase in the growth of Twitter, and comes as the company is experiencing a series of outages and challenges with its infrastructure and performance. The announcement also reinforces the attractiveness of Salt Lake City as an emerging data center hub. Twitter is the third high-profile technology company to build a major data center in Salt Lake City, following the lead of eBay, Oracle Corp. and the NSA.

Twitter currently manages its infrastructure through a managed hosting agreement with NTT America, which has cited Twitter’s growth as a driver in the expansion of its data center network. In April Twitter announced plans to build a data center of its own. On Wednesday it provided additional details on the Twitter Engineering blog.

“Later this year, Twitter is moving our technical operations infrastructure into a new, custom-built data center in the Salt Lake City area,” wrote Twitter’s Jean-Paul Cozzatti, who said having dedicated data centers will provide more capacity to accommodate growth of 300,000 new users per day. “Keeping pace with these users and their Twitter activity presents some unique and complex engineering challenges. Importantly, having our own data center will give us the flexibility to more quickly make adjustments as our infrastructure needs change.”

Twitter also said it will expand its network to include providers other than NTT America. Twitter’s reliance upon a single company has been a topic of debate during some of the company’s outages, including a denial of service attack last August. “We will continue to work with NTT America to operate our current footprint, and plan to bring additional Twitter managed data centers online over the next 24 months,” Cozzatti wrote.

Twitter’s plans will be welcomed in Salt Lake City, which has won several major projects that scouted locations across the western United States:

• In May eBay unveiled a $287 million data center in South Jordan, Utah, which will host the eBay.com and Paypal.com web sites.
• Oracle recently resumed construction on a $300 million data center in West Jordan.
• The National Security Administration (NSA) is investing more than $1 billion in a large new data center at Camp Williams in Utah that will provide infrastructure to support its intelligence-gathering operations.

The Utah market has also been attractive to regional data center providers. C7 Data Centers and ViaWest each have multiple facilities in the Salt Lake City area.

For more, see our coverage of Adam’s presentation at Velocity 2009. For additional video, check out our DCK video archive and the Data Center Videos channel on YouTube.

The ubiquitous microblogging service was unavailable for about 80 minutes yesterday morning. “We’ve identified the cause of today’s incident as an error with networking equipment, Twitter said on its status page. “This networking error prevented us from serving at full capacity.”

Twitter also noted this morning’s elevated error rates – which display the “Fail Whale” or perhaps a message that Twitter is over capacity – but soon reported that the incident was resolved and the system is “functioning normally.” The Netcraft monitoring indicates that although Twitter is up, its response time remains higher than usual.

As of Noon Eastern time, one of the phrases trending on Twitter is ” Twitter Over Capacity.”