Why can't iSCSI+LVM2 build on Proxmox?

Question

ubuntu

Good day, colleagues.
Given:

• 3 Proxmox nodes (5.2-10). Diskless (OS loaded with NFS), virtualok disks - LVM2 over iSCSI
  
• Homemade storage: Ubuntu Server 18.04, stgt. It has 4 HDDs and 1 SSD: 2xRAID1, on one of the raids - bcache with SSD. The server presents 2 iSCSI (according to the number of raids).
  

Actions BEFORE:

• One HDD disappeared (from the raid without bcache). The system lives, but the raid is on the same wing.
  
• "On the sly" updated all the nodes, the PM minor changed (if I remember correctly - from the 2nd to the 10th) . Everything works, one raid is still on the same wing (there were reboots, everything went up as always) .
  
• Turned off the virtual machines
  
• Turned off the storage, changed the screw (oxide) power cable , turned it on, the raid gathered and recovered.
  
• I checked iSCSI locally on storage - everything is OK:

  # iscsiadm -m discovery -t st -p 127.0.0.1 -t st
  127.0.0.1:3260,1 iqn.2018-06.pz:fast
  127.0.0.1:3260,1 iqn.2018-06.pz:slow

  
  
• I try to run virtual machines - they do not take off, they argue with the lack of a screw. That LVM (over iSCSI) does not connect, which indicates a raid with bcache (I remind you: the screw fell off on another raid)
  

Next, there were attempts to understand what was wrong:

On the PM node (127.0.0.1 - storage address):

# iscsiadm -m node -R
Rescanning session [sid: 1, target: iqn.2018-06.pz:fast, portal: 127.0.0.1,3260]
Rescanning session [sid: 2, target: iqn.2018-06.pz:slow, portal: 127.0.0.1,3260]

# vgs
  VG      #PV #LV #SN Attr   VSize   VFree  
  vg_slow   1   0   0 wz--n- 803,75g 803,75g

# vgscan 
  Reading all physical volumes.  This may take a while...
  Found volume group "vg_slow" using metadata type lvm2

## Вырезал все лишние NFS и SMB хранилки, с ними все ОК
# pvesm status
Name           Type     Status           Total            Used       Available        %
Fast            lvm   inactive               0               0               0    0.00%
Slow            lvm     active       842792960               0       842792960    0.00%
iFast         iscsi     active               0               0               0    0.00%
iSlow         iscsi     active               0               0               0    0.00%

On storage:

# vgs
  VG      #PV #LV #SN Attr   VSize   VFree  
  vg_fast   1  22   0 wz--n-  <1,82t  <1,17t
  vg_slow   1   0   0 wz--n- 803,75g 803,75g
## Выхлоп ниже сокращен, суть - диски виртуалок видит.
# lvs
  LV              VG      Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  vm-101-disk-1   vg_fast -wi-a-----   5,00g                                                    
  vm-101-disk-2   vg_fast -wi-a-----  30,00g                                                    
  vm-1200-disk-1  vg_fast -wi-a-----  30,00g                                                    
  vm-1200-disk-2  vg_fast -wi-a-----   5,00g

Where can you dig? Who can faced similar?

Answer 1

Check fdisk partitions on fast iScan