Config HW Raid control all disks or mixed between HW & PCI?

[carbonti]

I've purchased an Areca ARC-1220 PCI-e card. I plan to used this under a raid5 config with LVM2. The Areca cost over 3X what the motherboard cost of the computer its going into. It appears to be a pretty robust piece of gear. I expect this investment to safeguard my data and improve storage management. Resizing my old fixed partition scheme looked like a cross between a bucket brigade and a chess match - hopefully to be no more.

Some questions on configuration and performance:

a) I was planning on the Gentoo system residing on a non-raid disk volume. Are there any pros and cons to doing this? Some have mentioned in the forums here that there might be trouble booting from a raid array, is this still the case?

b) I can set up disks either in raid volumes or as non-raid stand-alone disks on the Areca. Is it better to put the system disk there as a "pass-through" disk rather than installing the system disk on the SATA port on the motherboard? Is there higher performance in letting the Areca handle all the disc I/O?

c) Areca features a function for on-line capacity expansion which allows additional physical drives to be added into a volume set. The HW then rebalances the data across the newly expanded disk pack. Anyone with experience in this? Does it "just work"? Just resize the LVM2 side of things and go?! Being able to add large volumes will make doing backups actually possible, right now I got nuthin.

Thanks to all for any comments you may add.