仮想サーバーゲストを実行するUbuntu 20.04サーバー。
root@virtual3:/dev# dmesg | grep dm-11
[16067.090601] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[16140.884093] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[16208.242423] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[16280.839903] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[16400.942784] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[16443.928439] EXT4-fs (dm-11): mounting ext3 file system using the ext4 subsystem
[16443.929427] EXT4-fs (dm-11): warning: mounting fs with errors, running e2fsck is recommended
[16443.934501] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[16443.949457] EXT4-fs error (device dm-11): ext4_mb_generate_buddy:1147: group 4, block bitmap and bg descriptor inconsistent: 2731 vs 2732 free clusters
[41267.656921] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[41310.767963] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[41351.690443] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[41393.912918] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[41462.134997] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[41474.884928] EXT4-fs (dm-11): mounting ext3 file system using the ext4 subsystem
[41474.885747] EXT4-fs (dm-11): warning: mounting fs with errors, running e2fsck is recommended
[41474.890554] EXT4-fs (dm-11): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[41474.904432] EXT4-fs error (device dm-11): ext4_mb_generate_buddy:1147: group 4, block bitmap and bg descriptor inconsistent: 2731 vs 2732 free clusters
root@virtual3:/dev# ls dm*
dm-0 dm-1 dm-10 dm-2 dm-3 dm-4 dm-5 dm-6 dm-7 dm-8 dm-9
ご覧のとおり、/dev/dm-11がないので、次に何をすべきかわかりません。ルートドライブはSSD（dm-0〜dm-8を含む）で、既存のHDD（dm-9とdm-10を含む）があります。
魔法で解決された不明なネットワークの問題により、システムが失敗しました（たとえば、systemd-networkdを数回再起動します）。まだ解決策が見つからず、ログに何も見つかりません。これら2つの質問が関連付けられているかどうかわかりません。
この記事を書いている間、すべてがうまくいくようです。 smartctlはエラーを報告しません。