LVM : lvextend on striped volume

Question

This is my first question in "stack"-systems and... it's probably very silly.

Especially because I think I know the answer, but as it's about some production system with critical data, I'd like to be sure and have a little confirmation.

So, the situation.

We have a storage server which is connected to storage array (it's a DDN storage array composed with principal unit and an extension). The data volume on the server is a LVM volume.

Actually it's based on 6 physical volumes.

I was a little bit surprised when I discover that it has some strange stripe configuration :

[root ~]# lvs --segments
  LV          VG         Attr     #Str Type    SSize
  data        ddn        -wi-ao--    4 striped 114.00t
  data        ddn        -wi-ao--    2 striped  57.11t 

The volume was not created by me and I'm not sure about reasons for this configuration. May be there are two explanations :

a) initially the volume was created only with 4 PV; the 2 others were added later.

b) The first 4 PV are situated in the principal unit of storage array, and the 2 others are situated in the extension.

In any way, it works actually pretty well.

Now, I would like to add a new volume to my LVM. I have only one volume to add and it's not possible to add two volumes.

I successfully did pvcreate and vgextend.

But, when I try to do

lvextend /dev/ddn/data -l+100%FREE

it asks me about stripes. I'm a little bit confused.

Should I indicate

lvextend /dev/ddn/data -l+100%FREE --stripes 3

to try to add my volume to the group of data

ddn -wi-ao-- 2 striped 57.11t

or

lvextend /dev/ddn/data -l+100%FREE --stripes 1

because I have only one volume so it could be only striped by itself (no striped as I understand).

The second possibility seems to be correct. And the first one no (as we could not add a volume to already striped group, at least without some manipulations).

I read this article : https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/5/html/logical_volume_manager_administration/lv

Especially point 5.4.9. Extending a Striped Volume and it seems to confirm my idea that I should do "--stripes 1", but I would like to be sure.

Another additional question. If the answer "stripes 1" is correct. In RedHat article they said :

If you do not have enough underlying physical devices to extend the striped logical volume, it is possible to extend the volume anyway if it does not matter that the extension is not striped, which may result in uneven performance.

Do you think it will really impact the performances?

The performance issue is important for us, but not critical. So if it could impact performances a little and in some cases : it's acceptable for us. But if it could really slowdown our system... I do not know that to do (as I said I could add only one PV, it's not possible to add another PV at the moment).

Thanks for your help. And sorry for silly question.