4 ms·
"You can wait for group commit acknowledgement with the getLastError command. When running with --journal, the fsync:true option returns after the data is physi
by dmytton 16y ago
"You can wait for group commit acknowledgement with the getLastError command. When running with --journal, the fsync:true option returns after the data is physically written to the journal (rather than actually fsync'ing all the data files). Note that the group commit interval (see above) is considerable: you may prefer to call getLastError without fsync, or with a w: parameter instead with replication. In releases after 1.8.0 the delay for commit acknowledgement will be shorter."
http://www.mongodb.org/display/DOCS/Journaling http://www.mongodb.org/display/DOCS/Journaling
- rbranson 16y agoRTFM'ing myself in public. While it's a great step forward, the whole thing sounds pretty immature at this point. It'll be a good day when this stuff matures and MongoDB has fsync:true and --journal by default, much to the chagrin of sensationalists everywhere. They'll really need to add some major smarts into the journaling and group commit if they're going to be able to stack up concurrent I/Os to help feed big disk arrays and even to get the best use out of SSDs which make back-and-forth latency on the I/O pipes even more significant.