I want to install a Linux OS on our HP DL380 Gen8 server. I have a question regarding the configuration of RAID on the disk. HP has their own software for initial setup like in RAID, etc...I think its called smartstart. Do I have to use this to configure raid on the server or Shall I use linux to configure the raid? What is is the best to use?

If you have a hardware RAID controller then you intercept this during the startup sequence (F8 from memory) and you can then configure the RAID Controller through the on-screen interface.

smartstart is a bootable DVD that provides a logical step-by-step setup of the hardware, raid controller and initial OS installation. To be honest, haven't used it in years, from power-on / reboot I just use the onboard software on the RAID card.

Once you've partitioned your drives they will be presented to the OS as though they were a single regular drive. As the hardware RAID controller is handing all the RAID "stuff" the OS doesn't need to be RAID aware or have any other specific modules/software installed.

Here we generally use a mix of disks, so we'll have something like 2x146Gb mirrored for /boot and swap and then a bunch of additional disks in RAID 5/6/10/50 for /

There's also HP System Management Homepage (and related software) that you could install on your server which can also provide a web-based interface to the RAID controller.

Would the swap require to be on a separate disk or partition?

Your choice depending on how you want to use your hardware. swap is (generally!) a separate partition. Where that partition resides is up to you.

Unless you use swap files instead of swap partitions.

Hence the "(generally!)" in my reply.