Here's a pic with some useful info:

As you can see, I have 2 drives and both of them are connected to the VIA controller (in the manual is reported to be as the one integrated in the southbridge). My partitioning setup is as follows:
/dev/sda1 contains Slackware
/dev/sda2 is empty
/dev/sda3 is empty
/dev/sdb1 is the swap partition
/dev/sdb2 is a "storage" partition
I gave all of them the ext4 filesystem, except for the swap partition obviously.
Now, the first time I tried to install Sabayon (it was the 4.2 version) in /dev/sda2, I noticed something was wrong, because:
- the installer didn't recognize the first hard disk properly (with its partitions);
- the installer did recognize the second hard disk, but with some kind of free space after the "storage partition", which obviously doesn't exist (I think it is because of the not-recognized first hard disk);
I didn't take this seriously and I just installed everything right away (bootloader included).
I rebooted, but GRUB couldn't find the files on the Hard Disk.
Then I booted again the LiveDVD and checked the situation with fdisk, and I noticed that the partition table of the first disk was damaged and all the data on it was lost. Thank god I made a backup of all my personal files on a USB drive.
Anyway, I had to try again. After at least other 4 full installations, in which I'm sure I correctly rebuilt the partition table of my disks each time (I even tried the auto-partitioning tool of the installer, but it gave the same result), I started googling the strange /dev/mapper/pdc_* naming of the hard drives that the Sabayon installer gave me, but I wasn't able to find out much.
The only thing I suspected is that it had something to do with the Promise controller on the mobo (that anyway I don't use, so it would hardly make sense).
So when Sabayon 5.0 came out I decided to give it a try again. I backed up everything, disabled the damned Promise controller on the BIOS (the MOBO is an Asus K8V SE Deluxe), booted into the LiveDVD, and it installed everything without gaving me errors, but when I rebooted: boom! Corrupted partition table on the first drive and all data on /dev/sda1 lost.
I also tried to:
- install on /dev/sdb2 instead of /dev/sda2
- update the installer (I was desperate)
- swap the disk order in the bios
- go through the text installation
- call my mom (lol)
but nothing could solve the problem. All the times, I get this strange naming scheme of the hard drives, the data on the first disk gets corrupted, the installer creates a non-existing partition after /dev/sdb1 (a /dev/sdb2 that I noticed only with fdisk) and in the end I just can't make Sabayon work.
Plus, the fact that I had this same issue on both 4.2 version and 5.0 version makes me think that it could be a problem related with the installer itself, because fdisk launched from the LiveDVD can see /dev/sda1 /dev/sda2 and /dev/sda3 correctly and I never had a problem when I installed Ubuntu or Slackware. Even when I installed Gentoo from a stage3 (a nearly-traumatic experience for a newbie, lol) the system booted fine.
Thanks in advance.
PS: go easy on my grammar. I know it's not perfect, but english is not my primary language since I'm from Italy ^^
