initrd (initial ramdisk) provides essential kernel modules and drivers (e.g., for storage and filesystems) needed during the early boot process before the root filesystem is mounted.

The error message "special device /dev/data/files does not exist" suggests that the volume group data is not activated. From the lvsand vgsoutput:
- The logical volume files exists within the data volume group.
- The volume group (VG) and logical volume (LV) appear correctly listed, but they might be in an inactive state due to maintenance.

This process state represents zombie processes, which have finished execution but still remain in the process table because their parent process has not yet read their exit status.

Copying the public SSH key to the remote server's authorized_keys file is all that's needed to enable passwordless SSH authentication.

Password expiry policies ensure that even if a password has been compromised, its period of validity is limited, reducing the risk of long-term unauthorized access.