ArangoDB: What durability guarantees does ArangoDB offer..The FAQ Statement

Question

I just want to make sure I get this... in order to get the 'durability' factor right, all I need to do is make sure the 'wait for sync' option is provided or set globally on the collection and I'm 100% guaranteed the write is on disk, that the data is "synchronized immediately" correct (minus the part about the O/S lying to us)?

Answer 1

For each collection, you can set 'wairForSync' to either 'true' or 'false'. If you set it to 'true', then the call to save, update or delete a document in that collection will wait until the O/S has reported that the change has been written to disk. As you wrote, the O/S or the hard-disk might be lying.

The same is true if you set 'waitForSync' to 'true' in a call of 'save', 'replace' and so on.

Each block has a checksum. If the server crashes while ArangoDB is writing a document, it will check on start-up, if the write was successful or not.