NAS BACKUP PLUGIN ERROR

##### ISSUE TYPE

* Bug Report

##### COMPONENT NAME

~~~
NAS BACKUP PLUGIN
~~~

##### CLOUDSTACK VERSION

~~~
4.20
~~~

##### CONFIGURATION

##### OS / ENVIRONMENT

Ubuntu 22.04 / NFS

##### SUMMARY

The Jobs failing with error "jobresult":{"errorcode":530,"errortext":"Failed to create VM backup"},"jobinstancetype":"Backup","created":"2024-12-05T13:42:24+0200","completed":"2024-12-05T13:42:24+0200","jobid":"b22226f7-2d2b-43fa-801c-61e5af8a6870"}}

##### STEPS TO REPRODUCE

~~~
Backup plugin has been enabled on the Zone side.
An offering is created.
VM is assigned to backup offering
a Backup is initiated manually from UI.
~~~

##### EXPECTED RESULTS

~~~
Take instance backup
~~~

##### ACTUAL RESULTS

~~~
A directory is created in the /tmp of the hypervisor running the VM
A folder under the VM name is created in the mounted nfs
The UI returns "Failed to create VM backup"
~~~

首先，在 Ubuntu 22.04/NFS 上启用 NAS 备份插件，复现手动 VM 备份，然后检查 530 错误前后的插件、虚拟机监控程序和 NFS 日志。备份成功完成且 UI 不再报告 "Failed to create VM backup" 即表示完成。

由索引模型根据 Issue 内容生成。