Joe Terranova on 20 Feb 2009 13:08:50 -0800

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Re: [PLUG] Final backup question, at least I hope so

>> I'd be interested in learning why ext3 is a poor choice as well...
> Actually, it was me who said to Adam that I thought ext3 was perhaps
> not the best choice for such a large external drive. (I never said
> "poor"). I was wondering if a different journaling system would be
> more appropriate, for speed mostly, and also perhaps for size of
> partition. I said I thought I had heard that one of the other choices
> (such as XFS) might be better. Not ResierFS, which I personally had
> problems with in the past, and I am unsure of it's continued
> development).

Well the problem with journaling is that each write goes like this*:
write it to the journal
write it to the main filesystem
remove it from the journal

It's 2 writes and a delete instead of one write, so you're actually
sending the data twice. That would be why it'd be a problem. Using
ext2 would give faster write speeds. So on slower hardware  (old PCs,
and usb hard drives) or hardware where 2 writes is detrimental (SSDs),
a non-journaling file-system would be faster.

> So it was more of a question than a pronouncement. I've been told that
> ext3 is ext2 with journalling added in. And perhaps using a FS
> designed from the start as a journalling system would be a better
> choice.

I actually like that about ext3. It means you can use it with drivers
/ OSes that only support ext2. For that matter, ext4 is just ext3 plus
extra stuff.

* I am not an expert on journaling file systems. This might be completely false.

Joe Terranova
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