我有一台装有 Ubuntu 20.04 的服务器，运行一段时间没有问题。然而，从一周前开始，问题开始出现，一切都变得很慢。在服务器上，我运行 Virtualizor 和许多 VM（VPS）服务器。
看起来一切都很慢，因为 iowait 很高。服务器运行 3 个三星 870 QVO 1TB SSD。有人能解释为什么 iowait 这么高以及如何解决吗？
命令：iotop -aoP
454444 be/4 root 0.00 B 0.00 B 0.00 % 15.71 % [kworker/u130:3-events_unbound]
453682 be/4 root 0.00 B 0.00 B 0.00 % 4.63 % [kworker/u130:1+flush-8:0]
1053 be/3 root 0.00 B 96.00 K 0.00 % 4.44 % [jbd2/sda5-8]
5710 be/4 libvirt- 6.27 M 9.02 M 0.00 % 1.29 % qemu-system-x86_64 -enable-kvm -name guest=v1019,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libv~=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
3525 be/4 libvirt- 1276.00 K 15.32 M 0.00 % 1.21 % qemu-system-x86_64 -enable-kvm -name guest=v1017,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libv~=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
5766 be/4 libvirt- 2.18 M 3.39 M 0.00 % 0.79 % qemu-system-x86_64 -enable-kvm -name guest=v1018,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libv~=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
11654 be/4 libvirt- 44.00 K 1200.00 K 0.00 % 0.72 % qemu-system-x86_64 -enable-kvm -name guest=v1012,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libv~=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
5811 be/4 libvirt- 0.00 B 976.00 K 0.00 % 0.61 % qemu-system-x86_64 -enable-kvm -name guest=v1004,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libv~=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
454732 be/4 root 0.00 B 0.00 B 0.00 % 0.11 % [kworker/1:0-events]
5869 be/4 libvirt- 0.00 B 28.00 K 0.00 % 0.11 % qemu-system-x86_64 -enable-kvm -name guest=v1201,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libv~=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
274709 be/7 netdata 1188.00 K 0.00 B 0.00 % 0.06 % netdata -D -P /var/run/netdata/netdata.pid
669 be/4 root 0.00 B 0.00 B 0.00 % 0.01 % [xfsaild/sda3]
752 be/3 root 0.00 B 3.66 M 0.00 % 0.00 % systemd-journald
1244 be/4 root 0.00 B 12.00 K 0.00 % 0.00 % python3 /usr/bin/fail2ban-server -xf start
1693 be/4 emps 0.00 B 16.00 K 0.00 % 0.00 % nginx: worker process
328592 be/4 syslog 0.00 B 164.00 K 0.00 % 0.00 % rsyslogd -n -iNONE