[gentoo-user] identical drives, different free space!

[Iain Buchanan <iaindb@netspace.net.au>]

Hi,

I have two 160Gb drives, one internal and one USB.  I've partitioned
them the same and created an identical filesystem on the USB drive for
backing up my internal drive.

I'm using the following rsync command to make the backup:
sudo /usr/bin/ionice -c 3 /usr/bin/rsync -aAx --exclude suspend_file
--delete --delete-excluded --partial
--human-readable / /media/root-backup

however, after running this command sporadically for a few days, the USB
partition is now full, whereas my root partition isn't!

sda is internal, and sdd is external.  sda7 is the one I'm interested
in:

$ sudo fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000080

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1          11       88326    6  FAT16
/dev/sda2   *          12        4875    39070080    b  W95 FAT32
/dev/sda3            4876        4888      104422+  83  Linux
/dev/sda4            4889       19457   117025492+   5  Extended
/dev/sda5            4889        7321    19543041   83  Linux
/dev/sda6            7322        7384      506016   83  Linux
/dev/sda7            7385       19457    96976341   83  Linux

Disk /dev/sdd: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5d5d0036

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1          11       88326    6  FAT16
/dev/sdd2              12        4875    39070080    b  W95 FAT32
/dev/sdd3            4876        4888      104422+  83  Linux
/dev/sdd4            4889       19457   117025492+   5  Extended
/dev/sdd5            4889        7321    19543041   83  Linux
/dev/sdd6            7322        7384      506016   83  Linux
/dev/sdd7            7385       19457    96976341   83  Linux

I just deleted a bunch of /var/tmp and distfiles to free up some space,
and ran the rsync again.  Now it looks like this:

$ df -h
Filesystem            Size  Used Avail Use% Mounted on
rootfs                 92G   81G  6.1G  93% /
/dev/sdd7              92G   89G  4.6M 100% /media/root-backup

/dev/sda3              99M   39M   55M  42% /boot
/dev/sdd3              99M   39M   55M  42% /media/boot-backup

I'm doing the /root backup from cron, but the /boot backup manually when
I make changes.

I thought perhaps the ext3 options were different (ie. different amount
of "reserved" space) but that would make the "Avail" columns different,
and shouldn't make the "Used" columns different.

any thoughts as to why my USB partition is full?  thanks,
-- 
Iain Buchanan <iaindb at netspace dot net dot au>

Most people have two reasons for doing anything -- a good reason, and
the real reason.