Re: SES Enclosure Management.

[NeilBrown <neilb@suse.de>]

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On Tue, 14 Feb 2012 10:30:37 -0700 Robert Woodworth
<robertjwoodworth@gmail.com> wrote:

> Has anyone ever thought of integrating SES managed enclosures into the
> kernel RAID system?  I briefly looked through the archives and have
> not found anything on the topic.
> 
> Some HW based RAID controllers do this flawlessly now, there is no
> reason why the kernel RAID cannot also.  (LSI MegaRAID)
> 
> 1) When a drive is part if a managed enclosure, the RAID system should
> address it by location instead of by enumerated device node.  The SES
> device in the enclosure can map the physical slot to a physical drive.
>  The RAID admin (mdamd) should be able to add/fail/identify devices
> based on slot.

Does this just mean that the admin should using names in /dev/disk/by-path/
rather than /dev/sdXX to address devices?  What can md or mdadm do to help?

> 
> 2) If the RAID system fails a drive, it should notify the SES
> management and turn on the fail bit and the fail LED.

"mdadm --monitor" will run a script on drive failure.  This could easily
notify the SES management.

So maybe all we need here is a script to plug in to mdadm... Would you like
to write one?

> 
> 3) The RAID system should be able to turn on the 'identify' bit and
> LEDs for an array or a single drive.

Again, it sounds like you just need a script to ask mdadm which devices are
included in a given array, and then do whatever magic is needed to turn on
the light.
It is fairly easy to extra the device list from the output of
  mdadm --detail --brief --verbose /dev/md/whatever

but it might be good to make it easier to extra from
  mdadm --detail --export /dev/md/whatever

Would you like to write such a script?

> 
> I'm currently doing firmware on a managed enclosure.  Although my
> vendor only supports LSI MegaRAID, there is no reason why my
> enclosures cannot work in the same manner on a kernel RAID system.
> 
> 
> 
> Request for comments...

It sounds to me like you just need a few scripts to provide some
enclosure-specific functionality.  I would be happy to include them in the
mdadm distribution.

Or maybe there is something that I didn't understand??

Thanks,
NeilBrown



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