Re: Linix-3.6.3 sda, sdb drives in reverse order (with a USB 2.0drives and a monolithic kernel configuration)

From: Wallak
Date: Fri Oct 26 2012 - 15:43:29 EST


Chris Friesen wrote:
On 10/25/2012 04:49 PM, Wallak wrote:
I've a very annoying behavior with the linux-3.6.x kernels release, and
a monolithic configuration. The USB 2.0 drives are mapped first with
/dev/sda, /dev/sdb... devices, and than the SATA AHCI drives come after.
This is out of order with the BIOS configuration and breaks a program
like lilo. This is also annoying when we use a static partition mapping.

Linux-3.5 works fine. Where this bug come from ? Is this a patch to get
the old, and classical behavior ?

As you have discovered it's fragile to rely on /dev/sd* names since a BIOS update, kernel update, or motherboard replacement could conceivably cause them to change.

Better to use something like partition labels that you control and that don't change.

Chris

You are right, when we have a configuration with a lot of drvies and adapters SATA, old SCSI,.. etc. the order may change. But having the main SATA hard drive defined, as the BIOS boot device, behind external and removable USB drives is in my opinion a bug.And may lead to security issues (drives with the same label, etc...).

Using =LABEL, or =UUID with a bootloader like grub or lilo, save the the boot device mapped drive partition number , and so booting on an older kernel like linux 3.5 will fail. If we remove the external USB drive, the boot process will fail too...

So such a bug have to be fix.


Wallak.

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