Linux – Are PERC 5/i RAID controller drivers available and easily installed on Ubuntu 9.04

You still should be able use the 1420SA at least as a usual SATA controller - it's driving chip (Marvell 88SX6541-BCZ) is supported by the kernel.

Even in "host raid" (aka fakeraid) mode you might check out if you can get dmraid to work with it, but usually it is not worth the trouble. You perfectly could set up a redundant md device and write the bootloader to both disks (I believe this is even supported by the Debian text installer) to achieve a very similar result with standard Linux tools which are independent from the storage controller.

The PERC 6/i is a dual-port controller; each port has 4 SAS lanes. On the 8x2.5in R710 chassis, that's a one-to-one mapping of front-panel disks to SAS lanes. On the 3.5in chassis, ports 6 and 7 are unused. With a 4-disk array, you could move 2 disks to slots 4 and 5 to split the workload between channels, although there's still the single processor and memory on the PERC card.

Updating firmware is typically a good idea, and is a fairly painless process (although it does require a reboot.)