On Sat, Feb 13, 2010 at 12:49 PM, <david@xxxxxxx> wrote: > On Sat, 13 Feb 2010, Justin Piszcz wrote: > >> On Sat, 13 Feb 2010, H. Peter Anvin wrote: >> >>> On 02/11/2010 05:52 PM, Michael Evans wrote: >>>> >>>> On Thu, Feb 11, 2010 at 3:00 PM, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> >>>> wrote: >>>>> >>>>> Hi, >>>>> >>>>> I may be converting a host to ext4 and was curious, is 0.90 still the >>>>> only >>>>> superblock version for mdadm/raid-1 that you can boot from without >>>>> having to >>>>> create an initrd/etc? >>>>> >>>>> Are there any benefits to using a superblock > 0.90 for a raid-1 boot >>>>> volume >>>>> < 2TB? >>>>> >>>>> Justin. >>>>> -- >>>>> 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 >>>>> >>>> >>>> You need the superblock at the end of the partition: If you read the >>>> manual that is clearly either version 0.90 OR 1.0 (NOT 1.1 and also >>>> NOT 1.2; those use the same superblock layout but different >>>> locations). >>> >>> 0.9 has the *serious* problem that it is hard to distinguish a >>> whole-volume >>> >>> However, apparently mdadm recently switched to a 1.1 default. I >>> strongly urge Neil to change that to either 1.0 and 1.2, as I have >>> started to get complaints from users that they have made RAID volumes >>> with newer mdadm which apparently default to 1.1, and then want to boot >>> from them (without playing MBR games like Grub does.) I have to tell >>> them that they have to regenerate their disks -- the superblock occupies >>> the boot sector and there is nothing I can do about it. It's the same >>> pathology XFS has. >>> >>> -hpa >>> >> >> My original question was does the newer superblock do anything special or >> offer new features *BESIDES* the quicker resync? > > the older superblocks have limits on the number of devices that can be part > of the raid set. > > David Lang > The 1.1 and 1.2 formats ALSO play more nicely with stacking partition contents. LVM, filesystems, and partition info all begin at the start of a block device; putting the md labels there too makes it obvious what order to unpack the structures in. -- 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
