Disabling Fsync in Laptop_Mode

There are several libraries that help you to disable fsync temporarily so your hard disk doesn't always spin up to save your notebooks battery. Of course that is not very flexible as you need to preload the libraries meaning you have to restart the programs.

Btrfs' Hot New Features

Check them out at Linux Mag.

Ext3 Partition Optimized for RAID5

Check the output of mdadm. It tells you the block size in chunks, which you will need.
mke2fs -j -E stride=64,stripe-width=320 -L LABEL /dev/md0

In my example the chunks size is 64k. I use 6 disks, out of which 5 carry data, so the stripe-width is chunks*5=320. See man mke2fs for more.

I always add this for even more speed:
tune2fs -o journal_data_writeback -O dir_index /dev/md0

List Open Files of a Process

lsof -p `pifof process`

provides an exhaustive list including libraries.

ls -l /proc/`pidof process`/fd

provides a list of only the "plain" files.

Undelete Files on the ext3 filesystem - Finally!

ext3undel finally delivers what was long thought to be pretty much impossible, even by the developers who wrote ext3: You can undelete files which were deleted in an ext3 filesystem.

The funny part is that many people are not yet aware of this and you may thus still make interesting findings in partition images, e.g. the popular VMware images.

Check out the article at Linux.com for more.

Protect Files

If you want to make sure a file or directory structure can not be modified by anyone, this command helps:

sudo chattr +i