NAME

ionrestart - ION node restart utility

SYNOPSIS

ionrestart

DESCRIPTION

ionrestart is a utility task that is executed automatically when an ION transaction fails, provided transaction reversibility is enabled (see ionconfig(5)). It should never need to be executed from the command line.

When an ION transaction is reversed, all changes made to the SDR non-volatile heap in the course of the transaction are backed out but changes made to ION's working memory are not. (Forward logging of these changes to enable automatic reversal on these relatively rare occasions is judged to impose too much continuous processing overhead to be cost-justified.) Because the state of working memory is thereupon in conflict with information in the heap, ionrestart is automatically invoked to reload all of working memory; because this would obviously threaten the stability of all running ION tasks, ionrestart gracefully terminates the tasks of the node (not only ION daemons but also applications), then reloads working memory from the recovered heap, and finally restarts the ION daemons. Applications that receive termination indications from ionrestart may choose to sleep for a few seconds and then automatically re-initialize their own operations.

ionrestart will attempt to restart all core ION protocols including LTP, BP, and CFDP, but any protocols which were not operating at the time of the transaction reversal are not restarted. Also, protocols that ionrestart has not yet been adapted to cleanly terminate and restart (including, at the time of this writing, BSSP and DPTC) are not restarted.

EXIT STATUS

"0"

ionrestart terminated normally.
"1"

ionrestart failed, for reasons noted in the ion.log file; the task terminated.

FILES

No configuration files are used beyond those required for normal ION node initialization.

ENVIRONMENT

No environment variables apply.

BUGS

Report bugs to ion-dtn-support@lists.sourceforge.net