<p>It is possible that nondeterminism depends on the SATA chipset, but I have a system in production where the drives are enumerated in the order they appear to the kernel. Furthermore... if I pull sdb out (yay hot swap) and put it back in, it'll get sdg (sdf is the last one assigned at boot time in this system).</p>
<p>I don't really worry about it, though, because I use the serial numbers, not the node names.</p>
<p>--<br>
Sent from my phone... a G2 running CM7 nightlies!</p>
<div class="gmail_quote">On Jun 16, 2011 4:56 PM, "David Tomaschik" <<a href="mailto:david@systemoverlord.com">david@systemoverlord.com</a>> wrote:<br type="attribution">> On Thu, Jun 16, 2011 at 4:38 PM, Jim Kinney <<a href="mailto:jim.kinney@gmail.com">jim.kinney@gmail.com</a>> wrote:<br>
>> Sort of but not quite all correct. The hard drive chain was not changed<br>>> totally. Non-deterministic for pci-bus devices but still traceable with<br>>> lspci. Always non-d for usb (pita)<br>>><br>
>> Hard drives follow a specific pattern:<br>>><br>>> BIOS spills data to sys about drive locations. Bus num followed by device<br>>> num. That doesn't change 'cause it can't.<br>>><br>
>> If a new drive is inserted at a lower bus num than other drives, it gets<br>>> called sda. Move the drive in socket 0 to socket 5 and it now is called sdf.<br>>><br>>> But so what?! Most distros use UUID anyway so you can move your drives<br>
>> around between boots and it'll still work as long as the BIOS knows where<br>>> the /boot drive is. Cool thing is error messages will reflect the current<br>>> configuration.<br>>><br>>> So if the bad drive is moved from sdb to sdf, on reboot the error will<br>
>> reflect the bad drive is sdf.<br>>><br>>> So as long as drives stay plugged in the same, detection will be<br>>> deterministic but the name is not. Remember, empty sockets 0-5 and a single<br>>> drive in 5 will be called sda.<br>
>><br>>> Thus by looking for the next to lowest numbered drive will reveal sdb, the<br>>> failed drive in the OP. :-)<br>> <br>> Unless, of course, there are udev rules that specify otherwise.<br>> Serial # is still the most reliable way to be CERTAIN of what you're<br>
> pulling. Removing the wrong drive from a RAID can make your day very<br>> bad. (I've placed SN labels on the visible end of drives in my home<br>> system for exactly this reason. Or paranoia. Or because I like<br>
> labels. Take your pick.)<br>> <br>> <br>> <br>> -- <br>> David Tomaschik, RHCE, LPIC-1<br>> System Administrator/Open Source Advocate<br>> OpenPGP: 0x5DEA789B<br>> <a href="http://systemoverlord.com">http://systemoverlord.com</a><br>
> <a href="mailto:david@systemoverlord.com">david@systemoverlord.com</a><br>> <br>> _______________________________________________<br>> Ale mailing list<br>> <a href="mailto:Ale@ale.org">Ale@ale.org</a><br>
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