Recently, after switching to open source drivers for my Nvidia card in notebook, I get possibility to have working suspend to disk (well suspend was always working, but the resume of screen was the problem). In same time, I enabled suspend to disk, when battery is getting really low in Gnome power management preferences. This night it saved me file system troubles - I let the notebook to do some calculations and forgot to connect it to power. So it ran few hours till the battery was down and then it just hibernated. When I noticed this on morning, I could just plug the power and the calculation can continue. Thanks to everybody who made this work.