What constitutes the "OS" for RHEL
 

I'm trying to load a server with two drives mirrored, then a bunch of bigger drives RAID5'd for data. I want to put the OS on the mirrored drives, then data and whatever else on the mirrored set. The two virtual disks show up, but I dont know what parts I should put on the mirrored drives.

I'm used to Windows where I would install Windows onto the mirrored virtual disk during the OS install, then all my data would be on the RAID5 virtual disk. But I don't know which of the following constitute the OS for linux or should be on the mirrored set rather than the RAID5?

/
/boot
/home
/opt
/tmp
/usr
/var

AFAIK, the usual convention is that the /home directory is used for user data, which you would want on your mirrored drive, as well as possibly the /var directory which generally contains log files and other changing system data. I might be inclined to also mirror /etc, as it tends to contain a lot of system-specific configuration data.
I hope others will contribute opinions on this also.
--- rod.

Thanks for the advice Rod. I hope to get a lot more recommendations and explanations on it, like you said. Seems like this a question every newbie would be asking himself.

You could put /home and /var on the RAID5 filesystem.
Your kernel's in /boot, your binaries are in /usr and opt doesn't do much on RH systems IMHO.

They will still appear as if they are all on / though, when viewing the filesystem.
Oh and swap should go on the faster disk too.

Just my 2c

Thanks smoker. Also, i forgot to mention, this server will have a couple samba shares (which I envisioned putting on the large RAID5 virtual disk) and run a very minor php website which will probably be buried in opt under lampp

Anyone else have an opinion on this? I'm still not really clear

I think it all depends just like everyone else has said. If I were going to create a server like how I understood your original post then:

Mirrored Drive: OS level data - ensures best uptime
/boot
/
/usr
/var
/tmp
swap

RAID5 Drive: Constantly changing data - non-os data - System will carry on without them until you can recover the data
/export
/home
/var/www/

This is just what I would do. I'm sure there are hundreds of reasons why this is not perfect..

Thanks JWL. and way to nicely lay it out for easy viewing :-)

I think on the mirrored set, i'm going to put

/boot
/
/usr
/var
/tmp
swap
/home (since only a handful of people actually log on to the server)

then on the RAID5, I'll do
/opt (which is where it appears all the other lampp sites i have on other servers are stored)
/data (for my samba shares)

I think that'll work ok, what do you guys think?