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Re: Weird.



On Fri, 16 May 1997, Alex Shnitman wrote:

> Note the /dev/hdb2 line. Used space plus available space gives us 741958
> blocks. The filesystem size, however, is 782378 blocks. Where are the
> missing 40420 blocks? Maybe it sheds some light on the missing space
> problem I wrote about a week ago. Is there anything like "lost clusters"
> on ext2? Where could these 40MB disappear?

The "culprit" is mkfs.ext2. Every _normal_ mkfs has a switch "-m":

glamis [~]: mkfs.ext2
mke2fs 1.06, 7-Oct-96 for EXT2 FS 0.5b, 95/08/09
Usage: mkfs.ext2 [-c|-t|-l filename] [-b block-size] [-f fragment-size]
        [-i bytes-per-inode] [-m reserved-blocks-percentage] [-qvS]
        [-o creator-os] [-g blocks-per-group] [-L volume-label]
        [-M last-mounted-directory] device [blocks-count]

This switch reserves at least SOME of the disk space for uid==0 usage.
Normal reserved range is 5%-10%. mkfs.ext2 selects 5%.


References: