copying directories

ccee · 01-29-2010, 08:00 AM

Hello
I've been trying to backup things to an external ext3 usb disk. In an effort to control the integrity I do a "du -s source_dir destination_dir" and in certain directories the size always comes out different. There always seems to be a difference of 4 bytes. Even if I do an individual md5sum on every file and the directories prove to be identical (at least file wise) the result of the du command seems to suggest otherwise. There are no .hidden files. Does anyone have any idea what this could be?
Thanks Chris

druuna · 01-29-2010, 08:52 AM

Hi,

One possible reason can be a difference in blocksize on the HD and the usb disk.

du shows disk usage as blocksize. I'm not sure what it uses by default (a fix number or the blocksize of the disk, I assume the latter). Try adding a fixed blocksize to the du command you use with the -B <number> option (du -sB 1024 <file/dir>).

Hope this helps.