> -----Original Message-----
> From: Eric Z. Ayers [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 10, 2000 6:46 AM
> To: [EMAIL PROTECTED]
> Subject: Loss of a SCSI device and RAID
>
> I've been wonder how this would work for a while.
>
> I know that the Linux kernel auto-detects the SCSI devices on boots
> and assigns them
>
> /dev/sda to the first one
> /dev/sdb to the second one ...
>
> and so on.
Yep. Lots of planning done there. :-)
> Doesn't this put a kink in your plans if you remove a disk physically
> and then restart the system? I mean, what if the failiure on the disk
> is something like smoke coming out of the drive bay and the next time
> you reboot the kernel doesn't even see the device?
If you're using just the SCSI drives, yes, it screws everything up.
> Is there a way to hard code /dev/sda to Target ID N and /dev/sdb to
> Target ID M so that in case N fails, your old /dev/sdb doesn't show up
> as /dev/sda when you reboot?
Sort of. There are some "devfs" patches that make the /dev filesystem MUCH
cleaner, and they keep disk at the same location, even when other disks are
removed. It does break a few things though. I don't think it currently
works with RAID, at least not on 2.2.x
> The setup I'm envisioning is a 2.2.16 kernel with the latest patches,
> a single SCSI bus with 2 hard drives in a RAID 1 configuration. If it
> makes a difference, the system will NOT boot from these disks.
Well, with persistent superblocks, you don't have anything to worry about.
The kernel will just detect your RAID sets, and configure them. Then, since
/etc/fstab is pointed at /dev/mdX rather than /dev/sdX, you don't have to
worry about SCSI drives changing. HTH,
Greg
