Hi, thanks for the answer. > Why would you want a RAID-1 without superblock. I generally > consider that a legacy configuration. Ah! I was thinking about it as a method to build a RAID with an already existing disk or partition, which cannot be modified. So, let's say I've already a disk with some data and I want/need to protect it with a RAID configuration, but I cannot re-create the RAID from scratch, because this will damage the content of the disk. Of course, if there is another solution, like having the superblock on a separate file, it would be nice too. BTW, have you ever consider that? > As there is no superblock, md cannot tell if the array is "clean" > or not. It assumes the worst. > If you know for a fact that the two mirrors are consistent, > then tell mdadm with "--assume-clean". Uhm, no, it is not clean, but one of the two has the correct data, the other no. Is the "-B" always copying from the first to the second or else? For example, I found consistent to create the array with the correct disk and "missing", then add the mirror. Of course, if there is a known order for the resync, then it would be enough to build the array with this in mind. The issue could also be that the "primary" disk could be updated alone, sometimes. > A bitmap (which has to be in a separate file) can be use Of course, it is a separate file... :-) > to record the clean/dirty status. It provides some of the same > functionality as a superblock. But it is not a complete replacement. OK, this is clear. > To quote from the man page: > > Because of this, the Build mode should only be used > together with a complete understanding of what you are doing. Exactly, I ran into that sentence, that's why I'm asking, I try to get the full understanding in order to see if I can use this "feature"... In any case, if this is "legacy", maybe better to forget about it. Thanks again, bye, -- piergiorgio -- 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
