I'm running Ubuntu from USB media, which has a drive capacity of 250 GB, all existing as one FAT32 partition.

However, when I created the bootable Ubuntu drive, only 4.79 GB were allocated for usage.

Rather than put files directly into the /cdrom where the drive is mounted, I want to expand what is listed here in aufs to be at least 200 GB. I'm hopeful that I can do this live.

Output of df :

Filesystem           1K-blocks      Used Available Use% Mounted on
aufs                   4051904   4050108         0 100% /
none                   1542852       284   1542568   1% /dev
/dev/sdb1            244076800   4901648 239175152   3% /cdrom
/dev/loop0              688000    688000         0 100% /rofs
none                   1547840      1496   1546344   1% /dev/shm
tmpfs                  1547840      4828   1543012   1% /tmp
none                   1547840        80   1547760   1% /var/run
none                   1547840         0   1547840   0% /var/lock
none                   1547840         0   1547840   0% /lib/init/rw

Output of fdisk -l :

Disk /dev/sdb: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 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: 0x00083fe4

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1       30401   244196001    c  W95 FAT32 (LBA)

So basically what I want to do is get /dev/sdb1 to be entirely, or almost entirely read as aufs.

I'm confused over how to do this, as the file systems are all part of /dev/sdb1 on one big partition, rather than separate partitions for separate file systems.