When dealing with hardware, you often see log messages like:
ata9: hard resetting link
ata9: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
To map an ata number to the actual sdX device:
ls -l /sys/class/ata_device/ata9/device/host*/target*/*/block
This shows which sdX corresponds to ata9. Check dmesg for the initial discovery mapping too.
Enjoy!