RFC: Suggesting ZFS "best practices" in FreeBSD

[Daniel Kalchev]

On 25.02.13 18:44, Karl Denninger wrote:
> On 2/25/2013 8:31 AM, Tom Evans wrote:
>> Using GPT labels is easy to do, and provides a cast iron guarantee
>> that your disk will not EVER be mistaken for a different drive.
>>
>> I put a GPT label on the drive, and then write it in permanent marker
>> on the top of the drive and on a sticky label that is stuck on the
>> front of the chassis. The disk label never changes in its lifetime, so
>> you only get issues if you insert a drive without labelling it first.
>>
>> Cheers
>>
>> Tom
>>
> Listen to this man.  Either do it in gpart or do it with glabel
> (depending on where you want it to show up); once done the drive will
> always have the same name in the device tree no matter what slot it
> shows up in.
>
> Then stick that label on the front of the drive carrier, and you never
> have this problem.
>
> Do that or suffer.  Your choice.
>

I can only second this advice.

Learn to make your setups as generic as possible. Wiring down device 
names using CAM etc, only complicates matters, at least because that 
knowledge is contained within the system you boot, not the drive. If you 
boot from an "recovery media", all of your "fine crafted" CAM wire-down 
system will be gone and you will suffer. You will suffer exactly at the 
moment when you need those labels most. Not wise.
Yes, Jeremy, there is always the first time.

Both glabel and GPT labels do the trick. Both behave differently and 
depending on your habits and intended usage one or the other is good. 
Just don't be inclined to use both at the same time. My personal 
preference as of later is GPT labels.

By the way, "glabel" is a generic term in FreeBSD. It refers to all 
label types, including those created with glabel, gpart and 
newfs/tunefs. The later are not really "geom labels", these are volume 
labels, but glabel is smart enough to detect/report them, even if it 
can't manipulate these labels. I don't find the glabel documentation all 
that confusing.

Daniel