fstab: When do you use the "dump" and "fsck" options?

Question

I found a great tutorial on how to use fstab: http://www.tuxfiles.org/linuxhelp/fstab.html

Using this tutorial, I was able to successfully get my SIMPLE mounting needs working. But during the article it says "I won't discuss [the dump and fschk options] in great length here (they would both need their own tuXfile)".

1. When is it good to use the "dump" option? How do you use the "dump" option?
2. When is it good to use the "fsck" option? How do you use the "fsck" option?

( Correct me if I am wrong but the dump option looks like could be useful for setting up auto-backups of a mounted drive (i.e. mount a network drive, then auto-backup the networked drive to a local harddrive where the network drive is currently mounted). )

Answer 1

From man 5 fstab :

"The fifth field, (fs_freq), is used for these filesystems by the dump(8) command to determine which filesystems need to be dumped. If the fifth field is not present, a value of zero is returned and dump will assume that the filesystem does not need to be dumped."

I think this is not really used today anymore. I have been administering linux desktops and servers for years and never, not once, changed the default settings here. dump is not even installed in any of my systems!

"The sixth field, (fs_passno), is used by the fsck(8) program to determine the order in which filesystem checks are done at reboot time. The root filesystem should be specified with a fs_passno of 1, and other filesystems should have a fs_passno of 2. Filesystems within a drive will be checked sequentially, but filesystems on different drives will be checked at the same time to utilize parallelism available in the hardware. If the sixth field is not present or zero, a value of zero is returned and fsck will assume that the filesystem does not need to be checked."

This one is perhaps a bit more sensible, but as explained here, set root to 1 and all others to 2, perhaps some other less important filesystems to 3 and so on.