Re: Advice about ext3, please

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> ext2 is problematic for removable drives because if you remove the drive
>> without cleanly unmounting it you risk losing your data.  So I would
>> recommend ext3 for such uses.  Performance is rarely an issue, actually.

> I use ext3 for my external USB drive.  Does this mean that I can remove
> it without cleanly unmounting it and not need to worry, or do you
> merely mean that I'd be less likely to lose data than if I'd use ext2?

Unmounting is always necessary if you want to make sure that your
changes are written to the disk, unless your filesystem doesn't do any
caching at all (don't know of any that does that, though there used to
be something called "supermount" to do that).

But with ext3, if you remove the drive without unmounting it, you should
expect to still have all your previous data: some of the recent changes
may be missing, but that's it.  With ext2 OTOH you may lose any part of
your disk's content, even files you haven't touched in a long while.
In practice fsck does a good job of recovering from such damage on ext2
(fsck is usually not needed at all for ext3).


        Stefan