I updated the ESXi version from 1021289 to 1065491 last week and the server crashed again this morning. There is another identical (hardware, software, config) server beside this one and it never crashed since it's in production, about 2 months ago. When it's not crashed, these servers are working very well.
I think the problem may come from a defective part (motherboard / hard drive / raid controller). I installed LSI SMIS Provider VIB when I installed ESXi, but hardware status tab never noticed about controller or hard drives issues.