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Disaster recovery, power and cooling secrets from Airtel data centers

Jasmine Desai, Principal Correspondent
The more extensive and complicated a data center gets, the more it becomes necessary to take a different data center management approach. This line of thinking definitely worked in favor of Bharti Airtel, when the company approached its data centers' disaster recovery,

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power and cooling setups from a different angle. Looking at Airtel's data center setup today, it all sounds like the result of a very well crafted plan—and it is.  
Goel's tips for data center power savings
1. Always have a modular data center design, especially for huge setups.

2. Have hot/cold aisle containment.

3. Regular maintenance of equipment is essential.

4. Always measure the end-to-end utilization of power.

Ever since its inception, Airtel has been at the forefront of technology, and has to its credit several innovations in the telecom sector. The company is structured into four strategic business units—mobile, telemedia, enterprise and digital TV.  Since Airtel's tier-3 data center was not only huge, but also critical to the company's functioning, the importance of disaster recovery at Airtel couldn't be over-emphasized. This is why Airtel took a different approach. "We have a unique data center strategy wherein we have divided the nation into four major zones—east, west, south and north. Our data centers are spread across India, and this way we have covered the whole geographical region." explains Rupinder Goel, the CIO of Airtel.

In addition to this arrangement, any particular zone has two data centers. Thus, Western India has two data centers—one in Mumbai and the other in Pune. Similarly, in the south, one data center is situated at Bengaluru and another in Chennai. These twin data centers in each zone back up each other. Likewise, one zone can back up another. These data centers are vendor- and industry-neutral, hence services from any industry can be hosted therein.  

Airtel's disaster recovery implementation was rolled out in 2007. Although consultants (such as Deloitte) were involved, it was mostly done in-house. Around 500 servers have been put on disaster recovery, and data has been replicated to the disaster recovery site. The company has a complete matrix for risk assessment. IBM and EMC storage is being used, while a DB2 and Oracle database is being used at the backend. There are around 2,000 servers in the data centers, the majority of them from IBM. The IT shop has been outsourced to IBM.

Commenting on Airtel's disaster recovery plan, Goel says, "The disaster recovery policy for most organizations is like a jewel, which is taken out only from time to time. For us, it is a live document. Twice a year, we execute our business continuity plan and test it completely on August 15 and January 26."

The data center power story

The disaster recovery setup at Airtel is closely interconnected with its power and cooling, just like in any other data center. The company has gone in for a very modular data center design, dividing it into different plates or modules. Organizations usually design data center cooling for the entire area, whereas Airtel has designed it in such a way that only the area which requires cooling gets it. Thus, in a high-density computing module, precision cooling and power have been put in.  

Another tactic is that servers of high density which need a 6 kVA rack are placed away from low-density ones needing 1 kVA. As Goel puts it, "Do not put apples with oranges. It is much easier to manage in modules than to manage an entire big floor."  

In addition, for the past two years, Airtel has been focusing on conserving energy. Power is suctioned as per the requirement of modules. The data centers also use hot/cold aisle containment; the cold aisle containment is closed with a door, so that the temperature remains constant.

Apart from this, Airtel is also experimenting with water chillers on top of the data center building. To start with, these have been installed in the Pune data center.  

Paying attention to simple things like regular cleaning of filters in the air handling unit has contributed a great deal to power and cooling efficiency in Airtel's data centers. Staffers also measure the power utilization from end-to-end; calculation is done right from the electric board to the diesel generator to the UPS to the panel to the rack and then finally to the servers. This helps Airtel's team determine the power utilization efficiency (PUE) ratios. Besides, server virtualization comes as a big power saver for the organization.  

"We are always experimenting with an increase in the temperature to find out how high we can go with it," informs Goel. "The recommendation is 18 degrees Celsius, but we go up to 22 degrees." The data center power infrastructure is from vendors such as Emerson and APC.  

When any business reaches a certain level, the various risks involved inevitably multiply. Keeping this in mind, disaster recovery readiness is an ongoing way of life for Bharti Airtel when it comes to its data and data centers.