Mount-paths
NetBackup for OpenStack incremental Snapshots involve a backing file to the prior backup taken, which makes every NetBackup for OpenStack incremental backup a synthetic full backup.
NetBackup for OpenStack is using qcow2 backing files for this feature:
qemu-img info 85b645c5-c1ea-4628-b5d8-1faea0e9d549
image: 85b645c5-c1ea-4628-b5d8-1faea0e9d549
file format: qcow2
virtual size: 1.0G (1073741824 bytes)
disk size: 21M
cluster_size: 65536
backing file: /var/NetBackupOpenStack-mounts/MTAuMTAuMi4yMDovdXBzdHJlYW0=
/policy_3c2fbee5-ad90-4448-b009-5047bcffc2ea/snapshot_f4874ed7-fe85-
4d7d-b22b-082a2e068010/vm_id_9894f013-77dd-4514-8e65-818f4ae91d1f/
vm_res_id_9ae3a6e7-dffe-4424-badc-bc4de1a18b40_vda/a6289269-3e72-4085-
adca-e228ba656984
Format specific information:
compat: 1.1
lazy refcounts: false
refcount bits: 16
corrupt: false
As can be seen in the example, the backing file is an absolute path, which makes it necessary, that this path exists so the backing files can be accessed.
NetBackup for OpenStack is using the base64 hashing algorithm for the NFS mount-paths, to allow the configuration of multiple NFS Volumes at the same time. The hash value is calculated using the provided NFS path.
# echo -n 10.10.2.20:/upstream | base64 MTAuMTAuMi4yMDovdXBzdHJlYW0=
If the path of the backing file is not available on the NetBackup for OpenStack VM and Compute nodes, the restores of incremental backups fails.
The tested and recommended method to make the backing files available is creating the required directory path and using mount --bind to make the path available for the backups.
#mount --bind <mount-path1> <mount-path2>
Running the mount - bind command will make the necessary path available until the next reboot. If it is required to have access to the path beyond a reboot, it is necessary to edit the fstab.
#vi /etc/fstab <mount-path1> <mount-path2> none bind 0 0