[linux-lvm] Got only half the space of RAID10 LV with 4 PVs (similar to RAID1 cause LV shows it has 4 'Mirrored volumes')

[runappz]

Thank you for clarifying it sir. Then  for `-l 8` I expect all 
`lvolX_rimage_N`s has 4 extents rather than 8:

       --- Segments ---
       Logical extents 0 to 7:
         Type        raid10
         Monitoring        monitored
         Raid Data LV 0
           Logical volume    lvol5_rimage_0
           Logical extents    0 to 7
         Raid Data LV 1
           Logical volume    lvol5_rimage_1
           Logical extents    0 to 7
       ...


On 2018/7/18 22:15, Douglas Paul wrote:
> On Wed, Jul 18, 2018 at 09:25:37PM +0800, runappz wrote:
>>       lvcreate --type raid10 -m 1 -i 2 -l 24576 pve # created lvol1
>>       lvcreate --type raid10 -m 1 -i 2 -l 8 pve # created lvol2
>>       lvcreate --type raid10 -m 1 -i 2 -l 8 pve # created lvol3
>>
>>       lvcreate --type raid10 -m 1 -i 2 -l 8 pve # created lvol4
>>       lvcreate --type raid10 -m 1 -l 8 pve # created lvol5
>>
>> The default LE size was 4MiB, so that I expect lvol1 to be 2*4*24576
>> MiB, while other 4 are all 2*4*8 MiB. However, I only got 4*24576 MiB
>> and 4*8 MiB partitions. I tried to run `mkfs.ext4` on lvol3 and mount
>> it. `df` shows clearly that lvol3 is a 32MiB volume.
> The -l option is the final size of the LV, not the space used on each device
> for each stripe or mirror. So when you say -l 8, it means the LV has 8
> usable extents, so it is supposed to be 32MiB. It doesn't matter how many
> stripes or mirrors you have.
>