In the week or so that I've been using Mepis 8 from the 4 GB usb key on my EeePC 901,I've had at least 5 instances of a corrupted journal on the ext3 fs. Luckily this is easy to fix by booting to Ubuntu and, after making sure the two Mepis partitions were unmounted running
# fsck -y /dev/sdcX
On one occasion, however, fsck didn't work and I ended up having to re-install Mepis.
Now, the Mepis 8 install only offers ext3 and reiserfs as fs options. However, I really don't need the journaling system on ext3 and would prefer to change it to ext2.
There's quite a lot of useful info available on how to do this such as this, this, this, this and even this.
What I did was to open the Mepis /etc/fstab file and change the lines for / and /home to ext2 from ext3. Then I booted into Mepis and both mount and /etc/mtab show that both Mepis partitions are mounted as ext2 so that's good.
However, I couldn't find any /.journal file in Mepis either from Ubuntu or from Mepis itself. nevertheless, running fsck on the usb key partitions shows that both (supposedly still) ext3 fs's were clean. Strange.
There's always the tunefs option to remove (and create if required) the journal but I haven't tried this yet.
I'll wait to see if the journal corruption problems persist before going any further.