#Number TR-PDS-1997-003 #Title Group message logging without orphans for fast output commit #Author J. Roger Mitchell Vijay K. Garg #Abstract In current recovery algorithms, the problem of output commit is often not specifically addressed. Those schemes that do, incur high latency before the output message can be sent from the system. This latency typically involves synchronous writes to stable storage. In this paper we present a method of grouping processes which allows output commit to occur after a process has received acknowledgements from other processes. We keep the number of acknowledgements small by creating groups of processes within the system, each group $i$ tolerates $k_i$ simultaneous failures. Our experiments show that when $k_i=2$ or $3$, our algorithm performs output commit over three times faster than simply writing information to stable storage. Our algorithm is based on the family-based message logging approach, but our approach allows for $k_i$ simultaneous failures in each group, rather than just $k$ across the entire system. Our implementation of family-based logging also never blocks live processes and allows for parallel recovery during simultaneous failures, something that previous work has not accomplished. We introduce the idea of a recovery reply cut to do this. #Bib @InProceedings{, author = "J. Roger Mitchell and Vijay K. Garg", title = "Group message logging without orphans for fast output commit", booktitle = "", address = "", month = "March", note = 1997, note = "available via ftp or WWW at maple.ece.utexas.edu as technical report TR-PDS-1997-003" }