HP NonStop G-Series - Manual (Page 69)

Scheduled Synchronization
HP AutoSYNC User’s Guide—522580-019
4-9
ASYSYNCP process
For each user ID, uuu,ggg, there should be a file set configuration table named
SFggguuu. All file sets in these tables are fetched to the monitor’s memory and sorted.
Suspended file sets are discarded.
The monitor starts a local ASYSYNCP process for each unique combination of user ID,
known destination system, and batch ID. If a destination system is not available, the
monitor waits for a system message that declares that the remote system is available,
and then starts the appropriate processes.
After starting the ASYSYNCP processes, the monitor sends a message to each
process, containing all file sets that pertain to that process.
The monitor maintains (and checkpoints) a table of ASYSYNCP processes and
periodically checks that these processes are still alive. If any process fails, or if there
are network or CPU failures that affect these processes, the monitor takes an
appropriate corrective action. Simple failures will be retried three times immediately
and then once every 30 minutes.
If the administrator or a user issues a command that updates the SYNCUSER or
SFggguuu tables, the monitor determines which tables have been changed and
refreshes its list of active file sets. The monitor then analyzes what changes have been
made; the monitor can start or stop ASYSYNCP processes or simply send a new set of
file sets to an existing ASYSYNCP process.
The monitor responds to STATUS requests by the AUTOSYNC Command Interpreter
with the cached list of file sets and ASYSYNCP processes.
Each monitor process can manage up to 1024 ASYSYNCP processes.
ASYSYNCP process
The ASYSYNCP process receives the list of file sets that have been assigned to it from
the monitor. It alters its process-access ID to the user ID that is associated with the file
sets; it will use this user ID for all file access, ensuring that a user does not gain
unauthorized access to data.
The file sets are arranged on a schedule time-list and are processed as they become
ready. File sets in an ASYSYNCP are processed serially.
When a file set is processed, the ASYSYNCP process starts an ASYSYNC process on
the destination system. The ASYSYNCP process then gathers information about all the
files of the source file set and forwards them to the ASYSYNC process.
The ASYSYNC process responds with a list of files (or tables) to be synchronized.
ASYSYNCP fetches the files and forwards the data to ASYSYNC. When all data has
been forwarded, it waits for the ASYSYNC process to complete and return its status
and various file counts. Then, the file set is rescheduled according to the INTERVAL,
START, and STOP specifications.
ASYSYNCP then checks its time list of file sets and processes the next one at the
appropriate time.