ms-be2026 has a disk failure, which doesn't seem to have been handled gracefully by mdadm. Also, our tool which creates tasks for a broken disk seems not have triggered here.
The server is up and e.g. the Icinga check for SSH claims to be fine, but an actual login fails with an Input/output error.
When logging in over the serial console it can be seen that it's emitting the following error every second:
[14332545.636171] sd 0:1:0:1: rejecting I/O to offline device
Folllowed by occasional errors like:
[14332545.665788] EXT4-fs error (device md0): __ext4_get_inode_loc:4363: inode #526249: block 2097306: comm systemd: unable to read itable block [14332545.732880] EXT4-fs (md0): previous I/O error to superblock detected