[linux-lvm] stripped LV with segments vs one segment

[lejeczek]

On 11/04/17 18:37, Marian Csontos wrote:
> On 04/10/2017 04:27 PM, lejeczek wrote:
>>
>>
>> On 10/04/17 13:27, Marian Csontos wrote:
>>> On 04/10/2017 01:16 PM, lejeczek wrote:
>>>
>>>>
>>>> I had 3 stripe LV, you know, three PVs, and wanted the 
>>>> LV to have 4
>>>> stripes, wanted to add 4th PV, you can see it from 
>>>> above lvdisplay.
>>>
>>> What you want is "reshape" not extend. This was 
>>> committed as RAID
>>> feature to 2.02.169, but it is still somewhat 
>>> experimental. You would
>>> need to convert stripe LV to RAID0 (aka takeover) and 
>>> then reshape.
>>>
>> convert from stipe to raid0 would not preserve stripe 
>> sizes? is this
>> correct?
>
> It should keep stripe size and if it does not it is a bug.
>
then probably a bug, I don't have it as was on the console 
in front of me now, but should be easy to replicate.
I had stripe LV with 16KB stripe and conversion(successful) 
to raid0 said I got 64KB stripe raid0 - is how I remember it.


>> nor it would:
>>
>> -I/--stripesize not allowed for LV dellH200.InternalB/0 
>> when converting
>> from striped to raid0.
>
> As it says, the option is simply not allowed. Also it 
> would be meaningless - one can not change stripe size 
> while converting stripe to raid0. At least not in RHEL-7.3 
> (lvm2-2.02.166). This is supposed to work in 
> upstream/2.02.169, but keep in mind that is a new feature, 
> and it is altering data, so better keep a working backup.
>
>>
>>   LVM version:     2.02.166(2)-RHEL7 (2016-11-16)
>>   Library version: 1.02.135-RHEL7 (2016-11-16)
>>   Driver version:  4.35.0
>