HP NonStop G-Series - Manual (Page 64)

Scheduled Synchronization
HP AutoSYNC User’s Guide—522580-015
4-8
Schedule Management
Schedule Management
The following overview describes how AutoSYNC manages scheduled
synchronizations.
Monitor Process
The monitor process accesses the SYNCUSER table to determine the users that have
been configured by the administrator. Each user has various parameters such as
maximum priority. A user may be suspended, in which case it is ignored.
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 the remote system is available and then starts
the appropriate processes.
For each ASYSYNCP the monitor passes 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 processes fail, or 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, respectively, the monitor determines which tables have been
changed and refreshes it’s 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
The ASYSYNCP process receives the list of file sets that have been assigned to it. 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.
Note. Disabling log down simply prevents use of another user ID by the Super user. The
Super user still has unfettered access to all data on the system. Using a privileged ASYSYNCP
to bypass disabled log down does not compromise data security.