> If your C* process dies and/or is killed you should not lose data. It's > written to the commit log before the client is acked, however that entry may > not have made it to disk yet in the case of commitlogsync=periodic. So, if > you kill the C* process you're fine. If you nicely restart the OS, you > should be fine (assuming your boxen/raid controllers/disks/etc do the sane > thing). If you nuke your OS, then see above about losing data on CL.ONE.
Being fine in case of killing Cassandra does depend though on Cassandra still guaranteeing that it write():s to the fd prior to ack even in periodic mode. I haven't checked, but I sort of took the default position of assuming it did not unless otherwise specified. If it does, and if this is an intended guarantee, that's great (and I'll happily submit a patch to make this explicit in docs/comments). Can anyone confirm/deny that this is an intended guarantee? -- / Peter Schuller
