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

Fri Sep 5 20:05:57 UTC 2014
m.roth at 5-cent.us <m.roth at 5-cent.us>

Valeri Galtsev wrote:
> 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 ;-) ?

Then you make something an extended partition.
>> 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

How? I've had them move around on a non-RAID m/b (for example, a drive
fails, and you put one in an unused bay, and then you've got, say, sda,
sdc and sdd, no sdb, until reboot), and even then, it's *still* a guessing
game as to whether hot-swap bay upper left, lower left, upper right lower
right are sda, sdb, sdc, sdd, or sda, sdc, sdb, sdd, or, for the fun one,
lower right is sda....