The DKRZ system was procured in two phases that are roughly have the same size. The storage of the first phase consisted of ClusterStor 9000 storage devices.

Both systems are configured in Scalable System Units (SSUs); pairs of servers in active/active fail-over mode that manages an extension unit (JBOD containing additional devices), resulting in two OSTs per OSS.

The peak performance is derived from the maximum performance possible on a ClusterStor 9000, that is 5.4 GiB/s, multiplied with the number of servers in the SSU/extension pairs we have installed (31 in phase 1.

Performance has been measured using Parabench. With Lustre DNE phase 1, DKRZ distributes the load among 5 metadata servers The observed performance was roughly 25 kOP/s on the root MDS and 15 kOP/s on each DNE MDS resulting 80 kOPS/s. Then five folders have been pre-created and distributed across the MDS. Then five Parabench were started at the same to create the typical workload behavior. The benchmark runs for a considerable time on 16 nodes with 16 processes per node but does not explicitly synchronize between the individual parabench runs. Theoretically, a single Parabench run could handle this setup, but the simpler approach has been chosen.

Performance of the phase 1 system has been measured with IOR using POSIX I/O to one file per process. The configuration was as follows:

• Sriping across 84 OSTs = 21 SSUs + 21 extension units
• 168 compute nodes, 6 IOR procs per node
• Arguments to IOR: -b 2000000 -t 2000000
• The amount of data was about 3x main memory of the used nodes