On 01/04/15 19:46, Alireza Haghdoost wrote: >> Now, how can be assured, in that case, that the "cache" >> > device is safe after the power is restored? > You do sync write-ahead logging on the Flash cache. If it return > successful, you do fire the writes to the RAID. If system crash/fails > during the RAID writes (Write-hole), you just recover data by scanning > write-ahead log in the flash cache and replay the logs into the RAID > drives. > Just to throw something nasty into the mix, I'm not sure whether it's SSDs or SD-cards, but there certainly *was* a spate of corrupted *controllers*. In other words, a power failure would RELIABLY TRASH the device, if it happened at the wrong moment. Hopefully that's been fixed ... Cheers. Wol -- 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
