[ https://issues.apache.org/jira/browse/CASSANDRA-3950?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Peter Schuller updated CASSANDRA-3950: -------------------------------------- Attachment: CASSANDRA-3950-1.1-v3.txt {{v3}} attached. Third time's the charm. I made it {{in_kb}} instead too, because I realized that megabyte resolution is not necessarily enough for really low-latency cases on a modern SSD (1 MB for a 90 MB/sec seq. writing SSD is 11 milliseconds). > support trickling fsync() on writes > ----------------------------------- > > Key: CASSANDRA-3950 > URL: https://issues.apache.org/jira/browse/CASSANDRA-3950 > Project: Cassandra > Issue Type: Improvement > Components: Core > Reporter: Peter Schuller > Assignee: Peter Schuller > Fix For: 1.1.0 > > Attachments: CASSANDRA-3950-1.1-v2.txt, CASSANDRA-3950-1.1-v3.txt, > CASSANDRA-3950-1.1.txt > > > Attaching a patch to support fsync():ing every N megabytes of data written > using sequential writers. The motivation is to avoid the kernel flushing out > pages in bulk. > It makes sense for both platters and SSD:s, but it's particularly good for > SSD:s because the negative consequences of fsync():ing more often are much > more limited than with platters, and the *need* is to some extent greater > because of the fact that with SSD:s you're much more likely to be e.g. > streaming data quickly or compacting quickly, since you're not having to > throttle everything as extremely as with platters, and you easily write fast > enough for this to be a problem if you're targetting good latency at the > outliers. > I'm nominating it for 1.1.0 because, if disabled, the probability of this > being a regression seems very low. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira