[linux-lvm] Proper way to delete an active snapshot?

Linda A. Walsh lvm at tlinx.org
Sat Sep 3 08:23:51 UTC 2011

Stuart D. Gathman wrote:
> On Tue, 30 Aug 2011, Linda A. Walsh wrote:
>> If you have a snapshot of a volume running... how are you supposed to 
>> delete
>> it?
>> i.e. after you unmount it... if I just do a lvremove, I get a warning 
>> about it being
>> an active volume -- so I tried doing a dmsetup remove on it first -- 
>> and that
>> stops the warning -- but I just noticed, I had a bunch of inactive 'cow'
>> volume names under 'dmsetup ls', that referred to the old snapshot 
>> names.
>> so I'm guessing that using dmsetup to remove the dev first, then 
>> lvremove is
>> NOT the best way to be doing this...(as it results in stuff that 
>> needs to be cleaned
>> up...)... So how do I remove the volume w/o getting warnings about it 
>> being 'active'?
> I agree that the warning is broken (when LV is not otherwise mounted 
> or open).
> I use
>   /usr/sbin/lvremove  -f "$snappath"
    Yeah...done that... doesn't feel right
> in scripts, which suppresses the warning without leaving a mess.  I'm not
> sure what happens if the LV is actually open in that case.  Hopefully
> you get an error.
I wouldn't expect that ... ... seems like -f could be for overcoming a
stuck driver -- in which case it might ignore a 'mounted' signal
from the kernel...  So that's why I asked...

The odd thing -- I used lvchange -- but it wasn't a mirrored or active 

I had:
  Home-2011.08.23-18.00.56 Home+Space -wi-ao   6.49g
  Home-2011.08.25-02.13.58 Home+Space -wi-ao   4.07g  
 *Home-2011.08.31-02.23.11 Home+Space -wi-a- 888.00m 
  Home-2011.08.31-07.34.53 Home+Space -wi-a-   1.86g
The one I removed was the one with the * beside it...
The one from yesterday morning didn't get filled up and mounted
either...but I still have the diff (maybe I copy it off manually..
rather than trust it to another run of my shell
script from hell..(what started out as a fun project has turned
into a personal demon!)...


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