Summary file

The summary file tracks global properties of a dataset, such as dataset id, its size, the total number of files, and the time it was created. It is stored in the dataset directory on the parallel file system. Internally, the data of the summary file is organized as a hash. Here are the contents of an example summary file.

VERSION
  6
COMPLETE
  1
DSET
  ID
    18
  NAME
    scr.dataset.18
  CREATED
    1312853507675143
  USER
    user1
  JOBNAME
    simulation123
  JOBID
    112573
  CKPT
    18
  FILES
    4
  SIZE
    2097182
  COMPLETE
    1

The VERSION field records the version number of file format of the summary file. This enables future SCR implementations to change the format of the summary file while still allowing SCR to read summary files written by older implementations.

A COMPLETE flag concisely denotes whether all files for this dataset are thought to be valid. The properties of the dataset are then contained within the DSET hash.

When fetching a checkpoint upon a restart, rank 0 reads the summary file and broadcasts its contents to the other ranks.