Re: [Hampshire] HDDs and UUID

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Author: Daniel Llewellyn
Date:  
To: Rob Malpass, Hampshire LUG Discussion List
Subject: Re: [Hampshire] HDDs and UUID
On 16 February 2017 at 12:21, Rob Malpass via Hampshire <
hampshire@???> wrote:

> Hi all (sorry for various tests, had forgotten which email account I use
> to subscribe to this list)
>
>
>
> At present, I have a (3.5” sata) drive connected to my Ubuntu machine via
> one of those docking station things – I couldn’t be bothered opening up the
> case at the time and as it’s only a media server, I thought no more about
> it.
>
>
>
> Now I’m considering buying a 4 bay JBOD enclosure and I’d like to move the
> drive into that. At present, the drive is mounted via putting its uuid in
> the /etc/fstab. Simple question (which I know I could work out just by
> swapping the drive but please humour me): if I swap the drive out of its
> caddy and put it into the jbod, will it still be noticed. The question
> I’m basically asking is : Is the uuid associated with the drive unit or the
> controller in the caddy?
>


​AFAIK the UUID is on the _filesystem_. i.e. using a cloner (dd) will
duplicate the UUID onto a separate partition - this can cause problems when
trying to mount-by-UUID due to two instances of the same supposedly unique
identifier. The 4-bay enclosure, if it is connected to a standard PC
exposing the disks as individual disks with partitions then everything will
carry-on working fine. However, if it is a "smart" enclosure (which exposes
a single device to a PC) or a NAS enclosure (connected to the network
rather than a PC) with it's own OS then you will likely not be able to
access the linux partitions on the drive because the enclosure wants to do
everything itself.

--
Daniel Llewellyn
--
Please post to: Hampshire@???
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