On 10/14/2016 06:06 AM, Ramon Hofer wrote: > From what I was reading [1,2] it is useful for faster rebuilds. > But why is it not present for md[1234] as I used the same command to > create these RAIDs? > Is it only possible for the last of the linear devices, or is it only > used for almost empty devices, or was the bitmap introduced in a recent > update? Bitmaps have been available for a long time, but including them on a new array by default is recent. They are most useful if a device is unexpectedly disconnected but otherwise OK. mdadm --re-add will allow that device to rejoin the array and only the missing data (tracked by the bitmap) will have to be written to sync it up. > I wonder if I should and could add a bitmap for the other devices as well? There is a performance hit, so it should be considered on a case by case basis. Phil -- 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
