ZOID
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Introduction
ZOID is an I/O forwarding component of the ZeptoOS project. Any communication between the compute nodes and I/O nodes (job management, file I/O, sockets) is facilitated by ZOID.
ZOID infrastructure consists of:
- Multithreaded zoid daemon on the I/O nodes which performs I/O forwarding for the compute nodes and which also communicates with the service node to perform job management,
- control daemon on the compute nodes which is responsible for job management tasks such as launching application processes, for the forwarding of stdin/out/err data, and for forwarding of IP packets,
- zoid-fuse daemon on the compute nodes which performs file I/O forwarding for POSIX-compliant applications.
User interface
User script
Right before a job starts running, and right after the last process of a job has terminated, ZOID daemon attempts to invoke a user script on I/O nodes. By default, the daemon invokes $HOME/zoid-user-script.sh (this pathname can be changed by an administrator). A single parameter is passed to the script: 1 at the job startup, and 0 at the termination.
Information about the job will be passed to the script in the following environment variables:
- ZOID_JOB_EXEC
- name of the job executable,
- ZOID_JOB_ARGS
- job arguments, separated by a :
- ZOID_JOB_ENV
- job environment variables, separated by a :
- ZOID_JOB_ID
- BG/P control system job id (Note: this is generally different from the Cobalt job ID; see FAQ for the latter),
- ZOID_JOB_GLOBAL_SIZE
- number of processes in the job (size of MPI_COMM_WORLD),
- ZOID_JOB_LOCAL_SIZE
- number of job processes handled by this I/O node,
- ZOID_JOB_MODE
- 0 for SMP, 1 for VN, and 2 for DUAL,
- SHELL, PATH, USER, and HOME
- will also be set...
Pset broadcast
Performance counters
Administrator interface
Command line options
-u
Programmer interface
Building a new plugin
Replacement libc?
