SATA and mixed devices

gloomy · 07-20-2006, 09:29 AM

Hi.

Few days ago I installed a third SATA hd on my desktop system (A8N-SLi with nforce4 and scsi_sata_nv driver; tested with few 2.6.16.x kernels). Everything works fine but I discovered that the system reads the drives falsely when compared to the physical connections and the BIOS.

Under BIOS I have everything correctly (sata1 = sata1, sata2 = sata2 and sata3 = sata3) but the system (likewise few live cd roms I tested) reads those drives as:

sata3 = /dev/sda
sata1 = /dev/sdb
sata2 = dev/sdc

Pretty weird for my understanding. Although the naming of the devices is hardly relevant as such, there were some annoyances for instance when playing with Grub, which, to my surprise, reads the drives correctly. So something wrong with udev or something similar?

appendix:

configfile=(hd1,0)/grub/grub.conf

title=Linux
lock
root (hd1,0)
kernel (hd1,0)/whateverkernel root=/dev/sdb5

osor · 07-20-2006, 01:19 PM

Can you post your udev configuration files.

gloomy · 07-20-2006, 02:01 PM

Nothing special there that I can see but sure (QUOTE REMOVED DUE IRRELEVANCE).

EDIT: I noticed that /dev/disk/by-path shows that the controller uses indeed a different address and the BIOS has an option to disable / enable sata 1+2 / sata 3+4. The above was for udev-087 on Gentoo but the problem is persistent with 096, which brought more problems than it solved. Whatsoever, the naming problem was easily solved by writing a simple set of udev rules and identifying the drives by names, i.e.

KERNEL=="sd*", BUS=="scsi", SYFS{serial}=="XXXXXASfs", SYSFS{model}=="Maxtor DFASDX", NAME="sda%n"

EDIT: However, I would appreciate if someone is able also to explain me why Grub is able to boot from root (hd1,0) and kernel (hd1,0)/kernel root=/dev/sdb5 (notice the mismatch because I have one IDE and three SATA drives) just fine, whilst after booting

Code:

grub> geometry (hd1)
drive 0x81: C/H/S = 38913/255/63, The number of sectors = 625142448, /dev/sda
   Partition num: 0,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 1,  Filesystem type unknown, partition type 0x83
   Partition num: 2,  Filesystem type unknown, partition type 0x83
grub> geometry (hd2)
drive 0x82: C/H/S = 19929/255/63, The number of sectors = 320173056, /dev/sdb
   Partition num: 0,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 1,  Filesystem type unknown, partition type 0x82
   Partition num: 2,  Filesystem type unknown, partition type 0x8e
   Partition num: 4,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 5,  Filesystem type is ext2fs, partition type 0x83
grub> geometry (hd3)
drive 0x83: C/H/S = 24321/255/63, The number of sectors = 390721968, /dev/sdc
   Partition num: 0,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 1,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 2,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 4,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 5,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 6,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 7,  Filesystem type is ext2fs, partition type 0x83

where the right boot partition is /dev/sdb1 = (hd2,0), which =! (hd1,0) at the perfectly working boot menu but (hd1,0) == sata1 at the BIOS. I thought Grub had nothing to do with the udev and such, and how does the BIOS probing of Grub work?