[linux-lvm] pvmove safety

[linux-lvm] pvmove safety

[Joseph L. Casale]

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How safe is pvmove in LVM2 when being operated on live volumes? I understand a backup is always a good policy as nothing can be 100% safe, but is the command known to produce unreliable results when used on a live filesystem? I am reading http://tldp.org/HOWTO/LVM-HOWTO/removeadisk.html and the warning up top is hard to miss, but I wonder if it's a bit outdated?

Thanks!
jlc

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Re: [linux-lvm] pvmove safety

[Jonathan Brassow]

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pvmove is pretty reliable.  However, I would probably make a backup  
before doing any sort of operation that would grow/shrink/move a file  
system.

  brassow

On Feb 12, 2008, at 3:25 PM, Joseph L. Casale wrote:

> How safe is pvmove in LVM2 when being operated on live volumes? I  
> understand a backup is always a good policy as nothing can be 100%  
> safe, but is the command known to produce unreliable results when  
> used on a live filesystem? I am readinghttp://tldp.org/HOWTO/LVM-HOWTO/removeadisk.html 
>  and the warning up top is hard to miss, but I wonder if it’s a bit  
> outdated?
>
> Thanks!
> jlc
> _______________________________________________
> 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/


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RE: [linux-lvm] pvmove safety

[Joseph L. Casale]

>pvmove is pretty reliable.  However, I would probably make a backup before doing any sort of operation that would grow/shrink/move a file system.
>
>brassow

Brassow,
Thanks for the reply, I was beginning to think it was a silly question <grin>. I couldn't find any reliable info regarding pvmove and the specifics of the actual command. I ended up just trying it and it worked.

I am also a little unsure about how IO to the LV in transit is handled, is it paused at any point?

If the pvmove is stopped at any point and an -abort is given, are all the PE's that *were* reserved automatically freed up? Also, I assume the old PE's aren't freed up until everything is copied over and in sync?>


Thanks!
jlc

Re: [linux-lvm] pvmove safety

[Alasdair G Kergon]

On Fri, Feb 15, 2008 at 12:21:12PM -0700, Joseph L. Casale wrote:
> If the pvmove is stopped at any point and an -abort is given, are all the
> PE's that *were* reserved automatically freed up? Also, I assume the old PE's
> aren't freed up until everything is copied over and in sync?
 
Read the pvmove man page: the operation is done in stages with checkpoints,
and an abort reverts to the last checkpoint.  So part might have moved
and part might not have moved.
No old PEs are freed until the whole operation completes (or --abort).

Alasdair
-- 
agk@redhat.com