Re: [BUG] non-metadata arrays cannot use more than 27 component devices

[Wols Lists <antlists@youngman.org.uk>]

On 25/02/17 23:41, Phil Turmel wrote:
>> Is there a sound technical reason not to go there, or is it simply a
>> > case of "learn another tool for that job"? The less tools I have to know
>> > the better, imho.

> Um, no, imnsho.  Learn new tools when you need them.

I don't have a problem with that. All too often people use the tool
they're familiar with when it's the wrong tool. But there's a reason
they do that - it's a familiar tool!
> 
> Linux raid has no formal mechanism to cleanly separate a mirror from a
> running array, access it as a backup, and not risk corruption when
> re-attaching it to the array.  Most filesystems write to the partition
> when mounting, even for read-only mounts.  You cannot safely access the
> disconnected member except via pure block reads.

Because to do so doesn't make sense? Or because nobody's bothered to do
it? I get grumpy when people implement corner cases without bothering to
implement the logically sensible options - bit like those extremely
annoying dialog boxes that give you three choices, "yes", "no", "yes to
all". What about no to all?

I feel like mirror-raid is perfect for doing backups. I take your point
that linux hasn't implemented that feature (particularly well), but
surely it's a feature that *should* be there. I know I know - "patches
welcome" :-)

Cheers,
Wol