NVP vProxy: FLR LVM Limitations

The FLR Limitations section contains the following two statements regarding LVM configurations on Linux VMs:

• LVM (Logical Volume Management) thin provisioning
• VM having any PV (Physical Volume) not allocated to a VG (Volume Group)

VMs containing these configuration types do not support vProxy FLR. The following processes can be used to help determine if unsupported LVM configurations are used.

The Linux lsblk command can be used to determine if a file system is mounted on an LVM mountpoint. Example:

[root@lnx-srvr01 ~]# lsblk
NAME                MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda                   8:0    0   60G  0 disk
├─sda1                8:1    0   63M  0 part /boot/efi
├─sda2                8:2    0    1G  0 part /boot
└─sda3                8:3    0 38.9G  0 part
  ├─vg_root-lv_root 253:0    0 19.9G  0 lvm  /
  ├─vg_root-lv_swap 253:1    0    4G  0 lvm  [SWAP]
  ├─vg_root-lv_var  253:2    0   10G  0 lvm  /var
  └─vg_root-lv_home 253:3    0    5G  0 lvm  /home
sdb                   8:16   0   20G  0 disk
└─sdb1                8:17   0 18.6G  0 part /nsr
sr0                  11:0    1 1024M  0 rom

LVM thin-provisioning:

On the Linux VM, run the following command:

sudo lvs -o+segtype

The output contains a column "type." Which may include the following:

• Linear: A simple, contiguous allocation of physical extents
• Striped: Data is striped across multiple physical volumes to improve performance
• Mirrored: Data is mirrored across multiple physical volumes for redundancy
• RAID: Various RAID levels (0, 1, 4, 5, 6, 10) are supported for different combinations of performance and redundancy
• Thin: Thin provisioning allows for over-committing storage, allocating space only as data is written
• Snapshot: A point-in-time copy of a logical volume, useful for backups and testing

Example:

[root@lnx-srvr01 ~]# sudo lvs -o+segtype
  LV      VG      Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert Type
  lv_home vg_root -wi-ao----   5.00g                                                     linear
  lv_root vg_root -wi-ao---- <19.94g                                                     linear
  lv_root vg_root -wi-ao---- <19.94g                                                     linear
  lv_swap vg_root -wi-ao----  <4.00g                                                     linear
  lv_var  vg_root -wi-ao----  10.00g                                                     linear

Alternatively, you can use the following command which returns only thin provisioned LVMs:

sudo lvs --segments --select 'segtype=thin'

If no output is returned, then no thin provisioned LVMs are configured.
 

LVM has a Physical Volume not Allocated to a Volume Group:

On the Linux VM, run the following command:

sudo pvs

Example:

[root@lnx-srvr01 ~]# sudo pvs
  PV         VG      Fmt  Attr PSize  PFree
  /dev/sda3  vg_root lvm2 a--  38.93g    0

The pvs command returns the Physical Volumes identified in the PV column. The output also contains a column showing which Volume Group (VG) that is assigned to the Physical Volume. If the VG column is empty next to a Physical Volume, the PV lacks a VG assignment, and FLR is unsupported. The recovery process fails. Example: NVP vProxy: FLR recovery fails with: Unable to import LVM objects

Conclusion:

If it is determined that the VM used LVM thin-provisioning or the LVM has a Physical Volume that is not allocated a Volume Group, vProxy FLR is not supported. To recover data from the VM, perform an Virtual Machine Recovery (Image Restore). To support FLR, changes would need to be made by the Linux Administrator to support FLR. FLR would only be supported on backups completed after the required changes are made.  

NVP vProxy: How To Perform A File Level Recovery When FLR Is Failing or Not Supported By the VM

NVP vProxy: FLR and Instant Recovery Fail for Cloud Based vCenter