On August 18, NHN Cloud showcased its new data center, NHN Factory X Seoul, located in Yangpyeong-dong, Yeongdeungpo-gu, Seoul. Lee Il-jun, head of the technology business division at NHN Cloud, explained the facility's water cooling technology, likening it to placing ramen in cold water to cool it down, as opposed to blowing on it to cool it with air. Despite the long rows of black server racks, the noise level was surprisingly low.
NHN Cloud has installed 7,656 NVIDIA B200 GPUs in this facility, utilizing water cooling to manage the heat generated by high-performance GPUs.
Inside the data hall, each rack accommodates up to six GPU servers. Above the racks, black piping runs to supply cold coolant and retrieve heated water from the servers. Cooling distribution units (CDUs) are located at the bottom of the racks.
Lee noted, "Air-cooled servers can be extremely noisy, but the current water-cooled environment operates at about 60 to 70 decibels," adding that the black pipes at the back of the servers are responsible for circulating the coolant.
Modern GPUs used for AI training and inference consume significant power and generate substantial heat. NHN employs a direct liquid cooling (DLC) method, using cold plates that come into direct contact with the heat-generating components of the GPUs and CPUs to effectively dissipate heat.
Lee explained, "Air cooling can handle about 30 to 40 kW per rack, but anything beyond that is very challenging. Currently, the racks here use around 130 kW of power." He added that future NVIDIA equipment will require even more power, making air cooling impractical for managing the heat.
While water cooling does not necessarily reduce costs, it requires separate cooling infrastructure and leak monitoring due to the use of water. However, it effectively removes heat generated by densely packed GPUs.
Lee mentioned that the existing data center lacked water cooling facilities, necessitating additional construction. Initial assessments estimated the project would take at least 10 months, but it was completed in about 4 to 5 months.
NHN Factory X Seoul is a 10-story data center with four underground levels. NHN Cloud occupies the 3rd to 6th floors, with AI computing resources for the government operating on the 3rd to 5th floors. Notably, the 3rd and 4th floors feature a large cluster of 4,080 B200 GPUs connected as a single computing environment. The 6th floor houses NHN Cloud's own AI cloud services and GPU infrastructure.
In total, there are 7,656 B200 GPUs, including large clusters like NIPA-CL1 with 4,080 GPUs and NIPA-CL2 with 2,040 GPUs. NIPA-CL1 and NIPA-CL2 rank 20th and 40th, respectively, on the global supercomputer list, TOP500.
Before exiting the data center, visitors observed the control room, where real-time monitoring of power, temperature, cooling, GPU, and network status was displayed on screens. Lee stated, "We continuously monitor power, temperature, and cooling status in the control room, and the operating system activates immediately if any anomalies occur." The control room operates 24/7, staffed by four personnel during the day and two at night.
* This article has been translated by AI.
Copyright ⓒ Aju Press All rights reserved.