[linux-lvm] Removing VG mappings using dmsetup tool

Zdenek Kabelac zkabelac at redhat.com
Tue Jun 23 21:02:04 UTC 2020

Dne 23. 06. 20 v 22:37 Gionatan Danti napsal(a):
> Il 2020-06-23 22:28 Zdenek Kabelac ha scritto:
>> Note - you cannot 'remove' mappings 'in-use'  (aka open count of a device
>> is higher then 0  - see 'dmsetup info -c' output for this).
>> However you can replace such mapping with 'error' target - so the
>> underlaying device is relaxed - although we do not support this
>> in lvm2 - you would need to use 'dmsetup' for this (and open lvm2 RFE
>> if there would be some serious justifaction).
> Not related to oVirt, but I would find a means to set an error target with LVM 
> quite useful - think about immediately stopping IO to/from device in case some 
> serious error happended. Using lvm rather than dmsetup would be easier and 
> less error prone.


ATM skilled admin can always easily enforce:

'dmsetup remove --force   vg-lv'

for i.e. linear devices to achieve this goal - however resolving this at lvm2 
is actually way more complex task when you start to consider the situation
should be at least 'somehow' recoverable - it's quite complicated and
not really highly demanded functionality.
It's more simple if you have constrained world of known types of devices
and known use-case you are targeting to solve.



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