[Tfug] joining two large files on disk...

[Jeremy D Rogers]

On Mon, Jun 14, 2010 at 6:27 PM, Kramer Lee <krameremark1 at gmail.com> wrote:
> I don't know about the linux file systems, but to do what he is
> talking about in the FAT file system, someone (not me) could write a
[snip]

Hmm.. interesting. Not me either. And this is ext4. But I think my
question has been sufficiently answered: no. :-)

> This could be a dangerous utility, dangerous like dd.  Merging two
> executable files, or anything with one executable file would probably
> hose it up irreparably.  It sounds like a person would want to
> consider carefully what multi-GB files should be merged this way.
> Unless the utility saved the original directory information etc, it
> wouldn't be recoverable, and as soon as the new big file is changed it
> wouldn't be recoverable.

I was really just curious if this was easy to do and I was missing
something, but the need to do it isn't that strong.

I was just playing with my new 2.5inch 1TB usb drive and testing
sustained write speeds between a couple of different drives by doing
things like "dd if=/dev/zero of=/media/1tbdrive/zeros". I got curious
how much difference it made as I got closer to the end (center) of the
platters, so after doing this a bunch of times I have files like
zeros1, zeros2, zeros3, etc. I didn't want to delete them because then
I would probably be writing to faster outer part of the platters
again, but after doing this a bunch, I thought it would be convenient
to merge them into a single file that just takes up space to force the
writes farther in without having 20 filenames. Pretty excellent logic,
eh?

In the end, this is a really poor way to test performance, and I think
there are utilities for this anyway.. but you know, once you start
asking yourself questions like is it possible, curiosity just takes
over.