ext 2 or 3? or the 3rd option (starts w/ an r?) reiserf or something.

As reiserfs is the default choice in slackware...

I use Ext3, it's really up to you.

What are the pros and cons of each?

I have no idea - when I started using Ext3, ReiserFS wasn't that stable (as I remember) and I just tend to stick to what I know.

I would highly recommend going with either EXT3 or ReiserFS, as journaling filesystems are more modern and advanced than the old school EXT2. Honestly, I haven't seen actual benchmarks between EXT3 and RFS, but people claim that they can perceive performance improvements with Reiser.

Might want to start with that as the default. No matter what you pick, it'll get the job done. Only thing with Reiser is that if you also use Windows and have PartitionMagic, it will only recognize EXT filesystems.

The ext3 file system is similar to ext2 with the addition of journaling and is the native linux filesystem. Reiserfs also has journaling. I think I remember reading that the Reiserfs wasn't quite ready when the 2.4 kernel came out and kernel support for it was added later. I think that the latest 3.x version of the Reiserfs supports access control lists. SuSE linux defaults to the Reiserfs and they are a major sponsor of this format. The XFS file system is supposed to be good for very large files systems ( hundreds of gigabytes ) and for video streaming applications.

The new Reiser 4 filesystem may be very different. If you go to the website, it's hard to find information on the Reiser 3 filesystem, because they are promoting the new technology.

There is also a file-system that IBM wrote ( JFS ) that may be better for very large servers.

Either the ext3 or Reiserfs may be best for desktops which are more likely to be shut down. For enterprise servers, and high speed streaming
either the XFS or IBM's JFS may be best.

Here is a web page dealing with comparing the performance and features of various file systems.
http://oregonstate.edu/~kveton/fs/

My recommendation would be to go with the default file system that your distro suggests. For Slackware, that's Reiser.

My reasoning is simple: If Patrick thinks Reiser should be the default, that's good enough for me (although in the past I used ext3). -- J.W.

It should also be noted that the longer you use Linux, the more aware of your needs and usage you become. So later on you might decide that a particular filesystem fits you better. In the meantime, though, I once again agree with the previous statements. Reiser or EXT3, either one, will do you right.

supposedly reiserfs is faster than ext3 with lots of smaller files, theoretically making it a good choice for the root filesystem with all those relatively small config files. i've always used it without problems, but some people have had problems with it (maybe before it became stable?) and still prefer ext3, which as the others have said is also a good choice.

Ext3 has always seemed to be a bit of a kludge, Reiser 3 is rock solid now and is fast. XFS and JFS are also sound alternatives with benefits for some server applications.

i gave reiser4 a shot and it didnt work out well. I have a secondary 40GB that i use to store movies and mp3 and the such on. it was really fast, but my dmesg was getting flooded with some errors, i cant remember exactly what they were at the moment, but it lead me to be uneasy with reiser4

Reiser 4 is still beta quality and is NOT for use on data that matters. Reiser 3 is stable, don't get them mixed up.

yeah, i knew reiser4 was beta, i had to go get the mm patch to even get it to work, and i would have made my main partition reiser3 if i had known it was better at the time, but i have this WAY too configured and tweaked to even think about reprograming.

For your root FS, I would go with Reiser. EXT3 is good, but it is really just a modification of EXT2. Reiser was designed from the ground up for journalizing, and has never failed me.

For file servers, I would put XFS on the storage drives. XFS is very fast for large files and large volumes. I have seen significant decreases in read/write times of large files on XFS compared to Reiser.