if e2fs is saying that the first backup superblock is at 32768 why do you
multiply it by 4 to get the 'real super block backup location? Why doesn't
e2fs do the multiplication to give the 'real' location? Is that a bug? If
so I think that can be easily fixed. Not by me ( don't have the know-how)
but by some one who knows how to program.
On Mon, Feb 20, 2012 at 8:59 AM, Matt Graham <
danceswithcrows@usa.net>wrote:
> From: Michael Havens <bmike1@gmail.com>
> > "sudo e2fsck -b block_number /dev/xxx"
> > The first backup superblock was at 131072. Are other
> > backup blocks located every 131072?
>
> No.
>
> dumpe2fs /dev/mapper/vg-usr32 | grep 'Backup super'
> Backup superblock at 32768
> Backup superblock at 98304
> Backup superblock at 163840
> Backup superblock at 229376
> [snip]
>
> Multiply those by 4, and you see the first backup is 131072, second is
> 393216,
> third is 655360, fourth is 917504, and they're spread even farther apart as
> they go up. A 7.9G filesystem here has 8 backup superblocks, while a 50G
> filesystem has 11. I'm not sure how the copies are distributed, but
> there's
> probably a fairly simple algorithm in the source for mke2fs that describes
> it.
>
>
> --
> Matt G / Dances With Crows
> The Crow202 Blog: http://crow202.org/wordpress/
> There is no Darkness in Eternity/But only Light too dim for us to see
>
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