...

Lise: 55 TiB - quoted

Emmy: 120 TiB - quoted

IME - Emmy only

DDN Infinite Memory Engine (IME) based Burst Buffers is a fast NVMe Solid State Disk (SSD) based data tier. Like Lise's FastIO this is especially helpful for random IO (especially random read) on large files.

Using the Burst Buffer for random IO helps to avoid overloading the global filesystem which results in slow job runtimes for all users. Beside the POSIX interface a native API and a MPI-IO module for further acceleration is available.

IME servers are currently available for use in EMMY.

Access: add the option --constraint=ime to your jobscript and use $IME_TMPDIR for a job specific folder or /ime/usr/$user for more permanent usage.

Size: 300 TiB

Finding the right File System

...

Especially random IO will be accelerated up to 200% using FastIO on Liseor IME on Emmy.

Performance Comparison of the different File Systems and SSDs for Emmy with IO500

Please remember that we are comparing here a single SSD for the node local SSDs, 360 SSDs for IME, 43 SSDs for Lustre SSD and 1000 HDDs for Lustre HDD using 32 IO processes per node. For the IME and Lustre filesystems 64 nodes were used to achieve near maximum performance for IME and the Lustre HDD pool. For the Home filesystem with its 120 HDDs only 16 nodes with 10 processes per node were used, as more nodes or processes overloads this small filesystem, resulting in even lower performance.

...