large ext2 image

qanopus · 11-16-2002, 09:35 AM

Hi there, i'm trying to make a 165 MB ext2 image ware i want to put some files on. First I made a blank image :
dd if=/dev/zero of=image.img bs=512 count=337920
Than I format the image as ext2:
mke2fs -i 1024 -b 1024 -m 5 -F -v image.img
And then I mount the image using a loop back device:
mount image.img /mnt -t ext2 -o loop

So far so good. I made an 165 MB image so I expect to be able to copy 165 MB to the /mnt directory. But I'm not. I can only copy about 50 MB. How come ?

Any ideas any one.

rootboy · 11-16-2002, 12:02 PM

Hmmm, I just tried it and it seemed to work for me, I managed to copy 150 meg to the file. Not know what the overhead is for ext2, I would say that I'm in the ballpark...

How many/how big are the files that you are trying to copy?

Ok, so now how do I get rid of it?

John

rootboy · 11-16-2002, 12:09 PM

P.S. umount image.img and see how big it is. Mine was 168 meg.

P.S.S. Neat trick

John

qanopus · 11-16-2002, 01:55 PM

In total there are 42 files. To get the total size of these files, I right clicked on the directory they were in (I'm using KDE 3) and clicked on "properties". When I do so, it says the file is 160.5 MB big. I'm sure my image is big enough. I did "ls -lh image.img" and it showed the file is a 165 MB's
What is an overhead ?

qanopus · 11-16-2002, 02:01 PM

Ok this is the strangest thing I have EVER seen. It works! I did exectly what I did before only this time it works. Sorry for wasting your time. I don't know what went wrong. Thanks for you reply though

michaelk · 11-16-2002, 02:12 PM

The meaning of Overhead in this case is the additional information required for the filesystem. As an example a MSDOS formatted 1.44 MB floppy disk is actually 2.0MB unformated.

qanopus · 11-16-2002, 02:31 PM

Whow, so you mean an unformated file systems is smaler then formated one's. I did'nt know that. He but that would mean that I could get more data on a floppy if I were to use an "better" file system.