Re: journaling file systems

[Jari Ruusu <jari.ruusu@pp.inet.fi>]

Newsmail wrote:
> I presume device backed loop
> device means that the entire device or partition is on the loop device, and
> it does not reside in a file.

Device backed means using a partition, example:

    losetup -e AES128 /dev/loop0 /dev/hda4
                                 ^^^^^^^^^
File backed means using a file that resides on some filesystem, example:

    losetup -e AES128 /dev/loop0 /home/jari/.my-secret-stuff
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
> what's up with this write caching thingie. I
> cant make a reiserfs filesystem on an encrypted device if I dont disable
> write caching? what will be the effect if I dont disable it?

If hard disk re-orders writes as a result of write caching, journal and/or
data may get corrupted under some circumstances. That applies both to
unencrypted and encrypted partitions.

> other question: if I remember I read something that there are ways to
> compile loop aes to the kernel. is there a way to compile the new
> twofish/blowfish/serpent modules to the kernel as well?

Yes, if you merge them to your kernel yourself. I prefer to keep them as
modules. They are easier to compile for all supported kernels as modules.

Regards,
Jari Ruusu <jari.ruusu@pp.inet.fi>
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