@olivierlambert Yes, i will update and have a look if it changes the behaviour anyhow. "For the rest, it's hard to answer without digging more." That`t exactly was i was looking for: Any Information where i can dig deeper? I`m looking for logs or traces of errors or so. It is not that i just wan`t this particular problem to be solved In my limited understanding of interal processes i think somehow a backup process dies and xo-server does not report or recognize this. But shouldn`t it somehow?

Questions for @julien-f I suppose

Its not solving it, but you can run echo 3 > /proc/sys/vm/drop_caches to release some of the cache again, without interfering with running processes. [root@host2 ~]# free -m total used free shared buff/cache available Mem: 15958 3308 158 8 12491 2355 Swap: 1023 177 846 [root@host2 ~]# echo 3 > /proc/sys/vm/drop_caches [root@host2 ~]# free -m total used free shared buff/cache available Mem: 15958 3308 2598 10 10051 2751 Swap: 1023 177 846