[CentOS] Order of sata/sas raid cards
Les Mikesell
lesmikesell at gmail.com
Fri Aug 24 14:49:23 UTC 2012
On Fri, Aug 24, 2012 at 9:24 AM, <m.roth at 5-cent.us> wrote:
> > I'll step into this again: let's look at the context.
>
> 1. a drive's failed. No conflict.
> 2. a server's failed, and you want something off one of its disks:
> a) you put it in a hot swap bay, and aren't rebooting the server -
> you are going to be manually mounting it, so no conflict
> b) you need to replace the server in -10 sec: you throw the drive(s)
> into a standby box, and either
> i. it's got partitions labelled /boot and /; fine, you
> *want* it to use those
> ii. you want a drive from another disk on that failed
> system: no problem - see 2.a.
> c) you have a system without hot swap bays, and you install
> the drive from the failed system, and then you do have to
> power up; this is the only case I can think of, off the
> top of my head where you have a collision. In this case,
> you need linux rescue, and relabel.
>
> So, where's the big issue with std. labels?
You power down, add some disks that you want to re-use. Maybe even
add a controller. Just because a bay looks like you can hot-swap
doesn't mean it is a good idea if you don't have to. You boot up.
When the label scheme was first rolled out, the machine wouldn't boot
if it found a duplicate. Now it will pick one. Possibly the wrong
one. As you might when you do a rescue boot for the relabel since you
won't know which controller is detected first.
--
Les Mikesell
lesmikesell at gmail.com
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