CentOS - Feb 2019 - What files to edit when changing the sdX of hard drives?

Phelps, Matthew wrote:
> On Thu, Feb 28, 2019 at 11:52 AM mark <m.roth at 5-cent.us> wrote:
>> Nicolas Kovacs wrote:
>>> Le 28/02/2019 ? 04:12, Jobst Schmalenbach a ?crit :
>>>> I want to lock in the SDA/SDB/SDC for my drives
>>>
>>> In short : use UUIDs or labels instead of hardcoding /dev/sdX.
>>>
>>> https://wiki.archlinux.org/index.php/persistent_block_device_naming
>>
>> Yeah - I strongly believe in labels, given the fact that *no* one can
>> remember a UUID....
>
> ls -l /dev/disk/by-uuid
> (copy)
> (paste)
That is, of course, assuming you have a running system, that you haven't
replaced a hard drive, an MDraid's not giving you trouble, etc.

And oh, I put that in another system, and it's also got partition one
labled boot... so? I'm not trying to boot off of it, I'm going to mount
it
on /mnt.

No, I dislike UUIDs. I dislike, strongly, lots of extra typing that
doesn't really get me anything. MAYBE, if you're in a Google or Amazon
datacenter, with 500,000 physical servers (I phone interviewed with them
10 years ago)... but short of that? Nope.

      mark

> No, I dislike UUIDs. I dislike, strongly, lots of extra typing that
> doesn't really get me anything. MAYBE, if you're in a Google or
Amazon
> datacenter, with 500,000 physical servers (I phone interviewed with them
> 10 years ago)... but short of that? Nope.
You can (perhaps should...) use the World Wide Name, which is a 
manufacturer ID unique to each disk. Contrary to the /sdX, it doesn't 
change with different configurations, OS or computer. An example of such 
an ID is the following:

/dev/disk/by-id/wwn-0x50025ee3b4f5ca61

Many modern disks have their WWN printed on their labels.

miguel medalha wrote:
>> No, I dislike UUIDs. I dislike, strongly, lots of extra typing that
>> doesn't really get me anything. MAYBE, if you're in a Google or
Amazon
>> datacenter, with 500,000 physical servers (I phone interviewed with
>> them 10 years ago)... but short of that? Nope.
>>
> You can (perhaps should...) use the World Wide Name, which is a
> manufacturer ID unique to each disk. Contrary to the /sdX, it doesn't
> change with different configurations, OS or computer. An example of such
> an ID is the following:
>
> /dev/disk/by-id/wwn-0x50025ee3b4f5ca61
>
> Many modern disks have their WWN printed on their labels.
>
Why? And if I'm partitioning it, that won't work anyway. I partition,
then
format with -l <labelname> and I don't *have* to change configuration,
if
I'm say, replacing a failed disk. The labels I use *mean* something -
root, export, etc. Why would I want a meaningless id? That's like
companies who name everyone's computer some id, rather than, say,
mrothltp?

Hell, a few hours ago, a manager came to me to ask about network issues. I
thought I'd try to ping his system, and asked him the system name.  Of
*course* he couldn't remember it.

Self-documenting ia useful, if not carried overboard.

      mark

On Feb 28, 2019, at 13:29, mark <m.roth at 5-cent.us>
wrote:
> No, I dislike UUIDs. I dislike, strongly, lots of extra typing that
> doesn't really get me anything. MAYBE, if you're in a Google or
Amazon
> datacenter, with 500,000 physical servers (I phone interviewed with them
> 10 years ago)... but short of that? Nope.
I?ve never in my career ever had to type out a UUID. 

You don?t need to be that big to benefit from automation.  Even small shops
would benefit from reproducible builds. Not every system needs to have loveingly
crafted artisanal partition labels.

All of this is moot, though, because I use lvm and so I just use
/dev/volumegroup/logicalname, and that?s all assembled automatically in the
kickstart. I only ever think about uuids when dealing with UEFI issues.

?
Jonathan Billings <billings at negate.org>