Fully document and implement parallel checkpoint support.
With the completion of SDP-900, anyone trained on the SDP can find
how to enable parallel checkpoints by looking at the "instance vars"
file, e.g. /p4/common/config/p4_1.vars. That contains the setting
DO_PARALLEL_CHECKPOINTS, with documentation on how to enable parallel
checkpoints.
However, the SDP Guide doesn't yet mention the feature. Changing from
a single-file checkpoint to a directory, while straightforward, is
a far-reaching change with impacts in documention and other scripts.
The command line to recover from a checkpoint directory is slightly
different, and examples in docs and scripts need to be updated.
Somethings that need to be reviewed and probably updated:
* SDP Guide - Add new section on parallel checkpoints.
* SDP Guide - Recovery procedures.
* SDP Guide - Scour for all references to checkpiont ops.
* Scripts that interact with checkpoints:
- load_checkpoint.sh
- mkrep.sh
- edge_dump.sh
- recover_edge.sh