Linux on an IBM x206m with SAS (Serial Attached SCSI) Hard Drives

I had to install Linux (Gentoo) on an IBM x206m server. Remarkable in this box is the use of SATA / SAS (Serial Attached SCSI) hard drives. Only very recent kernels support this kind of storage, and even so they need a firmware blob to be appropiately loaded for the controller to work at all.

Some references can be found on the Internet (although not many). Here is a quick reference of the steps involved to make this box work.

1. Install Gentoo on an external USB hard drive, or on a temporary IDE drive connected to server.

• I personally used an USB, 160 GB external hard drive (Memorex).

1. Compile the kernel, not forgetting to add support for SAS drives in the "aic94xx" module.

• Adaptec´s firmware must be downloaded from their website and included in the initramfs filesystem so it is available at boot time
  
• The loading order for the modules has to be changed in "initramfs"
  

1. Load aic94xx with modprobe and verify that the SAS drives are properly detected.
2. Proceed with normal Gentoo installation on the USB/IDE drive and later transfer the system to the SAS drives following the "custom stage4" from Gentoo

References:

• Adaptec aic94xx HOWTO from  Gentoo Wiki: http://gentoo-wiki.com/HARDWARE_Adaptec_aic94xx_with_bootable_software_RAID1
  • Note: this document suggests downloading the latest kernel sources from the git repository using "cogito". However, this seems not to be necessary anymore since kernel 2.6.23.11 now supports SAS for the aic94xx module.
    
• Custom Stage4 HOWTO from Gentoo Wiki: http://gentoo-wiki.com/HOWTO_Custom_Stage4