What is NSC Centre Storage?

The NSC Centre Storage system provides shared file storage for the Tetralith and Sigma systems.

It is intended for short- and medium-term storage during an active project using Tetralith or Sigma.

Using NSC Centre Storage

For information on how to use the system, please see our support pages

Storage system hardware

The storage system consists of one IBM ESS 5000 SC4 building block and one IBM ESS 3500 C3 building block.

The system occupies a single 19” rack and consists of 4 servers and 7 disk enclosures. In total there are 728 spinning hard disks. 422 of the hard disks have a size of 14 TB each, and the remaining 306 hard disks have a size of 20 TB each. The system also has a small number of NVRAM devices and SSDs which act as a cache to speed up small writes.

The total disk space that is usable for storing files is approximately 7.5 PiB. The difference between “raw” space on the disks and the usable space in the file system is mostly due to:

• RAID overhead¹
• The difference between a Tebibyte/TiB and a Terabyte/TB
• “Spare space” - unused disk space that is used to restore data redundancy when a disk fails.

The storage system is connected to Tetralith and Sigma. Each storage server has two 100 Gbit/s Ethernet links each. The Ethernet links are connected to IP routers that route between the storage system and Tetralith and Sigma’s Omni-Path networks.

History

The current NSC Centre Storage system was put into operation in October 2014 as three IBM GSS26 building blocks. Before it was connected to Tetralith and Sigma in 2018, Centre Storage’s servers and network interface were upgraded. In March 2020, a fourth building block (IBM ESS GL6S) was added, increasing the usable space from 2.7 PiB to 6.1 PiB. In September 2022, the old IBM GSS26 building blocks were replaced with a single new building block (IBM ESS 5000 SC4), increasing the usable space from 6.1 PiB to 6.9 PiB. In May 2024, the ESS GL6S building block was replaced with an ESS 3500 C3 building block, increasing the usable space to 7.5 PiB.