Ric Wheeler wrote:
You are absolutely right - if you do not have a validated, working barrier for your low level devices (or a high end, battery backed array or JBOD), you should disable the write cache on your RAIDed partitions and on your normal file systems ;-) There is working support for SCSI (or libata S-ATA) barrier operations in mainline, but they conflict with queue enable targets which ends up leaving queuing on and disabling the barriers.
Thank you very much for the information! How can I check that I have a validated, working barrier with my particular kernel version etc.? (Do I just assume that since it's not SCSI, it doesn't work?) I find it, hmm... stupefying? horrendous? completely brain dead? I don't know.. that noone warns users about this. I bet there's a million people out there, happily using MD (probably installed and initialized it with Fedora Core / anaconda) and thinking their data is safe, while in fact it is anything but. Damn, this is not a good situation.. (Any suggestions for a good place to fix this? Better really really really late than never...) - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
