File system issues

Hello. I'm using alpha 4.1, and I had the following problem: sometiemes, after a KDL error and the following reboot; I found that some changes in files are lost.

I know that probably that the last changes made in the filesystem can be lost, because of the characteristics of BFS; but I found that sometimes, the changes lost were made 4 o 5 hours BEFORE the KDL. Actually, I use the 'sync' Terminal command to "force" to apply the pending changes to the filesystem. Are they any settings to configure this automatically?

Sorry if my description is not very clear. English is not my native language.

Thank you!