[linux-lvm] Some questions on "Mirrors cannot be resized while active yet"

[linux-lvm] Some questions on "Mirrors cannot be resized while active yet"

[Simone Gotti]

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Hi all,

lvresize gives the message "Mirrors cannot be resized while active yet."
when trying to resize an active lv.

Simple tests using directly dmsetup let me resize a mirror on the fly
without problems (maybe I'm missing some problematic corner cases). With
a core log everything was resynced every time while with disk log only
the extended part was resynced. 

So, is there only missing code in lvm2 (curious to know if I should be
able to write the missing part) or also the kernel parts (dm-raid1,
dm-log and future dm-clog) needs some more code?

Thanks!

Bye!
-- 
Simone Gotti

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Re: [linux-lvm] Some questions on "Mirrors cannot be resized while active yet"

[Jonathan Brassow]

I don't remember all the reasons, but I *think* two of them were:
1) 186304 - potential to spoil redundancy
2) cluster mirroring needed ability to hold to identical logs for a  
short period

Both of these issues have been resolved, so it may be a simple matter  
of turning it on...

  brassow

On Aug 13, 2007, at 9:36 AM, Simone Gotti wrote:

> Hi all,
>
> lvresize gives the message "Mirrors cannot be resized while active  
> yet."
> when trying to resize an active lv.
>
> Simple tests using directly dmsetup let me resize a mirror on the fly
> without problems (maybe I'm missing some problematic corner cases).  
> With
> a core log everything was resynced every time while with disk log only
> the extended part was resynced.
>
> So, is there only missing code in lvm2 (curious to know if I should be
> able to write the missing part) or also the kernel parts (dm-raid1,
> dm-log and future dm-clog) needs some more code?
>
> Thanks!
>
> Bye!
> -- 
> Simone Gotti
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Some questions on "Mirrors cannot be resized while active yet"

[Jun'ichi Nomura]

Jonathan Brassow wrote:
> I don't remember all the reasons, but I *think* two of them were:
> 1) 186304 - potential to spoil redundancy
> 2) cluster mirroring needed ability to hold to identical logs for a
> short period

Maybe not a reason why it's disabled, but I think kernel code
needs to change to allow LVM mirror resizing.

LVM2 uses 'noflush' option for suspending mirror maps.

OTOH, currently you need full (flushing) suspend to resize device.
http://lkml.org/lkml/2007/1/19/136

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America