3 ms·
As I remember it: The journaling is only fsynced every so-often - its not like it magically gives you anything like the D in ACID. This leaves you relying on
by willvarfar 15y ago
As I remember it:
The journaling is only fsynced every so-often - its not like it magically gives you anything like the D in ACID.
This leaves you relying on replication for durability.
And everyone has problems when they lose one of the cluster.
Luckily it wasn't the lot: http://blog.empathybox.com/post/19574936361/getting-real-about-distributed-system-reliability http://blog.empathybox.com/post/19574936361/getting-real-abo...
I would love to be corrected; we'd all sleep easier.
- rogerbinns 15y agoHow about the actual facts: http://www.mongodb.org/display/DOCS/Journaling http://www.mongodb.org/display/DOCS/Journaling So yes it is periodic by default (in the millisecond range). However you can wait on any request until it has become durable. As for replication, people seem to have some hate for that, but the reality is that a journalled system that has failed (any database/operating system) will take a large amount of time to come back up, replay/recover journals etc. Not that useful.