[dm-devel] generic wrappers for multi-device FS operations

[Hannes Reinecke]

On 03/09/2011 04:13 PM, Ric Wheeler wrote:
> On 03/09/2011 09:23 AM, Alasdair G Kergon wrote:
>> On Tue, Mar 08, 2011 at 10:05:40AM -0800, Wendy Cheng wrote:
>>> So the "resize" is on the filesystem, not the volume ? The "grow" part
>>> is probably easy. Unfortunately, the "shrink" may not be easy for some
>>> of the filesystems:
>> The LVM situation today works both ways around.
>>
>> You can use 'lvresize' with an option to resize the filesystem too,
>> or use 'fsadm' with an option to resize the LV.  We felt that 'fsadm'
>> was a more-natural approach: allow the user to resize their filesystem
>> and automatically adjust the things underneath as necessary.
>>
>> Long term, we'd like it to be possible to configure a system for resizing
>> entire device stacks both top down (fsadm) and bottom up (triggered by
>> the
>> appropriate Unit Attention).
>>
>> (The current fsadm script was written as a proof-of-concept under the
>> constraint of just wrapping existing binaries. Of course there are
>> cleaner
>> ways to do it when you allow filesystem-specific code.)
>>
>> Alasdair
> 
> Is anyone actively looking at taken it beyond proof of concept?
> 
I'm working on the kernel-side parts, namely pushing unit attention
events out to userspace via debugfs.
There'll be daemon reading those and eventually triggering the
appropriate action.

We could hold a BoF at LSF or Collab summit, seeing that there is
quite some interest in these kind of things.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
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