Lösung: In der /etc/vzdump.conf -> tmpdir: /tmp eintragen
nano /etc/vzdump.conf
# vzdump default settings tmpdir: /tmp #dumpdir: DIR #storage: STORAGE_ID #mode: snapshot|suspend|stop #bwlimit: KBPS #ionice: PRI #lockwait: MINUTES #stopwait: MINUTES #size: MB #stdexcludes: BOOLEAN #mailto: ADDRESSLIST #maxfiles: N #script: FILENAME #exclude-path: PATHLIST #pigz: N
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