From the IceCube Laboratory the data deemed the most critical is sent via a NASA satellite called Transfer and Data Relay Satellite System (TDRSS) where it's sent to be stored in the University of Wisconsin - Madison's data warehouse. Data that isn't as critical is stored on tapes at the South Pole and then hand carried up to Madison by the first people to return after the drilling and summer season has begun. When those tapes arrive, they are transferred into the data warehouse.
In Madison, disk arrays store the data and servers provide the data to the collaboration for further analysis. At 60 Terabytes (approximately 60,000 Gigabytes) and growing, data storage and management demand a significant amount of equipment. Available storage hardware now includes 244 hard drives (ranging from 300 to 500 GB each, depending on age) in sixteen RAID enclosures. An additional 182 drives in seven RAID enclosures will be installed in the next few months, adding another 60 Terabytes capacity.
Currently six HP Proliant DL 380 servers share out the data to workstations and cluster nodes via NFS. The new storage will be connected to six HP Proliant DL 385 servers and connect to the workstations and cluster nodes primarily via IBRIX, a newer clustering file system which handles large amount of data and traffic better than NFS.
Redundant arrays of disks protect the data from individual disk failure. However, to protect against other forms of data loss (ranging from large-scale hardware failure and building-wide calamity to accidental erasure) tape drives back up the data and allow off site storage. The primary backup hardware, a SpectraLogic T950 tape library, currently holds four Sony SAIT tape drives and 250 SAIT tapes (500GB capacity per tape without compression), and backs up about 200GB/hour in its current setup, though the enclosure allows up to 950 tapes and sixteen tape drives. It would be impossible to back up all the data every night, but only a small fraction of the data changes each day (new, incoming data, or recently analyzed results). Each night the backup software recognizes recent changes and duplicates it, along with a fraction of the full data set, and over the course of eight weeks creates a full copy on tape.