This project transparently translates POSIX calls into native calls for DDN's Infinite Memory Engine (IME) .

The program interfaces directly with IME libraries. To generate the wrapper, run

$ make

To use the wrapper you need to set the LD_PRELOAD environment variable.

One time usage with ior:

$ LD_PRELOAD=<absolute_path_to_libposix2ime.so> ior

With Mvapich or Intel MPI:

$ mpirun -genv LD_PRELOAD <absolute_path_to_libposix2ime.so>

With OpenMPI:

$ mpirun -x LD_PRELOAD=<absolute_path_to_libposix2ime.so>

In addition, the IM_CLIENT_BFS_PATH environment variable can be set to contain the Backing File System (BFS) path used by IME (if mounted on the compute nodes). By default, if this environment variable is set:

• opendir calls are redirected to the BFS mount point on the compute node (accelerates subsequent calls such as readdir). Export the IM_CLIENT_NO_BFS_OPENDIR=1 environment variable to disable the feature.
• Buffer in DIR (directory descriptor) is enlarged from 32KB to about 1MB. It should make subsequent calls to readdir more efficient as more entries can fit in the buffer passed to getdents calls. Export the IM_CLIENT_NO_LARGE_DIR_BUFFER=1 environment variable to disable the feature.
• open with O_CREAT flag calls are split into a mknod call in the BFS mount point on the compute node followed by an open (without the O_CREAT flag) with the IME native interface. This feature improves create IOPs with Lustre. Indeed mknod does not allocate an OST object with Lustre. This is not needed as data is stored in IME. Export the IM_CLIENT_NO_MKNOD_CREATE=1 environment variable to disable the feature.