The ARM External Data Center, or XDC, routinely acquires, processes, and transmits data sets which are scientifically relevant and complementary to ARM data, but originate from external agencies. External data often include large data sets such as model and satellite data, which consume tremendous amounts of storage space, especially when batch processing is required. For example, the XDC recently processed derived satellite data from May 1998 to October 2007; nearly 2 TB data storage capacity was required to complete the processing. In November, the XDC completed a storage system upgrade to support ever-growing file storage needs and increase the speed of large batch processing. The new system consists of the newest mainstream disk technology called SATA disk arrays. This disk system provides fault tolerance (data will not be affected in case of a disk failure) and 9 TB of backup storage capacity.
The new system was put into place in phases, beginning with replacing old Sun systems with new rack-mounted servers that provide database, data transfer, and backup functions. Then the backup system was upgraded to provide both disk-to-disk and disk-to-tape backups. The disk-to-tape backup capacity is now 25 TB, and can be expanded to 33 TB. Four servers were added to the rack to handle increased web services and satellite data processing. And finally, the old disk storage arrays were replaced with new SATA arrays.