> -----Original Message----- > From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- > owner@xxxxxxxxxxxxxxx] On Behalf Of Martin Cracauer > Sent: Sunday, November 07, 2010 1:15 PM > To: linux-raid@xxxxxxxxxxxxxxx > Subject: Superblock V 1.2 > > I created a new array after upgrading kernel and OS > (2.6.32.25-cracauer and Debian/squeeze, respectively, resulting in > mdadm - v3.1.4 - 31st August 2010) > > The new array reads > md0 : active raid5 sdc2[4] sda2[2] sdb2[1] sdd2[0] > 292998144 blocks super 1.2 level 5, 256k chunk, algorithm 2 [4/4] > [UUUU] > > I figure the "super 1.2" means the new version of the superblock. It's one of the new versions, yes. Your statement suggests there is only 1 new version. > Can I read that array if I ever connect the machine to an older > kernel/mdadm? That depends on just how old. The new superblocks have been supported for quite some time. Worst case you will need to upgrade the old kernel to a newer one. > I see that I can control which version to use in > mdadm(8), but I don't get what the advantage of the new format is if I > don't run out of # of components or total capacity. The older 0.90 superblock is still quite serviceable for many uses, but unless the array is to be booted, I would recommend a 1.x superblock. > I can see how > storing the superblock at 4 KB makes it more robust against accidents > that wipe out of the first 512 bytes or similar fun. I think storing > it at the end will be a pain if you ever have to hexdump recover the > thing, no? Each one has its strong points and it drawbacks. You've got to decide which one will likely serve you best given your approach to managing your system. -- 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
