[CentOS] Bare drive RAID question, was RE: *very* ugly mdadm issue [Solved, badly]

Fri Sep 5 19:56:33 UTC 2014
Valeri Galtsev <galtsev at kicp.uchicago.edu>

On Fri, September 5, 2014 2:02 pm, Stephen Harris wrote:

> For me I have things like
>   sda1
>   sdb2
>   sdc3
>   sdd4
> and I align the partitions to the physical slot.

What do you do when it comes to 5,... (as MBR only supports 4 primary
partitions ;-) ?

> This makes it easier to see what is the failed disk; "sdc3 has fallen out
> of
> the array; that's the disk in slot 3".
> Because today's sdc may be tomorrow's sdf depending on any additional
> disks
> that have been added or kernel device discover order changes or whatever.

That's why I like the [block] device naming strictly derived from topology
of machine (e.g. FreeBSD does it that way), then you know, which physical
drive (or other block device, e.g. attached hardware RAID) a device
/dev/da[x] is. I remember hassle when Linux switched numbering of network
interfaces eth0, eth1,... from order the are "detected" in to reverse
order (which probably stemmed from pushing them into stack then pulling
them back) - or was it other way around?


Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247