Re: [PATCH} Add RAID devices.

[Chris Marusich]

Andreas Enge <address@hidden> writes:

>> How do you plan to address mdadm and grub config?
>> Will you be booting from RAID?
>
> the attached patch adds RAID support to our mapped device mechanism.

Cool!  Is it possible to use them in combination?  Using the example
From the documentation, would it possible to use LUKS to create an
encrypted /dev/mapper/home which uses /dev/md0 instead of /dev/sda3?

> +Alternatively, to become independent of device numbering, one may obtain
> +the LUKS UUID (@dfn{unique identifier}) of the source device by a
> +command like:

How difficult would it be to add support for specifying the sources
using UUIDs?  I know we could use use the device files in
/dev/disk/by-uuid/, but "(guix) File Systems" (footnote 2) recommends
against that: "Note that, while it is tempting to use
‘/dev/disk/by-uuid’ and similar device names to achieve the same result,
this is not recommended: These special device nodes are created by the
udev daemon and may be unavailable at the time the device is mounted."

> +The @file{/dev/md0} device can then be used as the @code{device} of a
> address@hidden declaration (@pxref{File Systems}).
> +Note that the RAID level need not be given; it is chosen during the
> +initial creation and formatting of the RAID device and is determined
> +automatically later.

I understand that in Linux, the device file names (e.g., /dev/sda3) can
sometimes change unexpectedly.  If they change later on, will anything
bad happen?

> +  #~(let ((every (@ (srfi srfi-1) every)))

Can't you just use "every" on its own?  It looks like you've imported
the srfi-1 module earlier on.

> +        (unless (every file-exists? '#$source)
> +          (format #t "waiting a bit...~%")
> +          (sleep 1)
> +          (loop)))

Does the code in this gexp get invoked every time the system starts up?
Why is a loop better here than an error?  What if the source device
files never show up?

Also, will that string be properly localized?

-- 
Chris

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