Extending LVM-pool error

[sodhi]

Hi all

I'm rather new to linux and completely new at managing disks through lvm, and I fear I might have borked something while extending my LVM-pool.

I just added a new 4TB disk (/dev/sdb). Until this point, I had one disk only (/dev/sda) with 2TB of space. After adding the new disk, I partitioned it (1 big partition of 4TB, /dev/sdb1) and formatted the partition with ext4.

I then followed this tutorial using vgdisplay to see available size to add to the LVM. Doing so with lvextend, however, gave me the error:

root@pve:~# lvextend -L+3.65TiB /dev/pve/vm-100-disk-1
Rounding size to boundary between physical extents: 3.65 TiB.
WARNING: Sum of all thin volume sizes (5.41 TiB) exceeds the size of thin pool pve/data and the amount of free space in volume group (3.65 TiB)!
For thin pool auto extension activation/thin_pool_autoextend_threshold should be below 100.
Size of logical volume pve/vm-100-disk-1 changed from 1.66 TiB (435200 extents) to 5.31 TiB (1392026 extents).
Logical volume pve/vm-100-disk-1 successfully resized.
​

Realizing I hadn't extended the 'data' pool:

root@pve:~# lvextend -L+3.65TiB /dev/pve/data
Rounding size to boundary between physical extents: 3.65 TiB.
WARNING: Sum of all thin volume sizes (5.41 TiB) exceeds the size of thin pools and the amount of free space in volume group (4.20 GiB)!
For thin pool auto extension activation/thin_pool_autoextend_threshold should be below 100.
Size of logical volume pve/data_tdata changed from 1.70 TiB (446404 extents) to 5.35 TiB (1403230 extents).
Logical volume pve/data_tdata successfully resized.​

I don't know where the 4.20GiB comes from, but that is also being reported by vgdisplay:

root@pve:~# vgdisplay
--- Volume group ---
VG Name pve
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 18
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 5
Open LV 4
Max PV 0
Cur PV 2
Act PV 2
VG Size 5.46 TiB
PE Size 4.00 MiB
Total PE 1430728
Alloc PE / Size 1429654 / 5.45 TiB
Free PE / Size 1074 / 4.20 GiB
VG UUID Ak8SHL-rW7M-UFaJ-zR59-NsQA-F3Jz-ks0Xcq​

For good measure, he is the output of vgs and lvs:

root@pve:~# vgs
VG #PV #LV #SN Attr VSize VFree
pve 2 5 0 wz--n- 5.46t 4.20g
root@pve:~# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
data pve twi-aotz-- 5.35t 30.30 48.18
root pve -wi-ao---- 96.00g
swap pve -wi-ao---- 7.00g
vm-100-disk-1 pve Vwi-aotz-- 5.31t data 29.67
vm-101-disk-1 pve Vwi-aotz-- 100.00g data 47.56​

So my question is: Are these warnings something I should be worried about? Should I have done something differently?

​

 

[wolfgang]

Hi,

You have to be worried about two things.

1.) If you extend an LVM, it is the same as you make a Raid 0 without the speed improvement.
What I mean if one Disk is failing all your data are away.

2.) You metadata pool is to small you have to resize it.
Because if it reaches 100%, your LVM could be damaged or in best case read-only forever.

If you are interested in your data, you should reconsider your LVM design because of point 1.