LCA Backup & Disaster Recovery 5 — Questions and Answers
Question 1: What does 'bare metal recovery' refer to in disaster recovery?
- Restoring a complete system to new or wiped hardware with no prior OS installed (Correct answer)
- Recovering only user data files without reinstalling the OS
- Restoring virtual machine snapshots
- Recovering from a RAID failure
Correct answer: Restoring a complete system to new or wiped hardware with no prior OS installed
Bare metal recovery restores an entire system image (OS, applications, and data) onto hardware that has no existing operating system.
Question 2: Which tool is specifically designed for bare metal backup and recovery on Linux systems by creating bootable rescue media?
- Relax-and-Recover (ReaR) (Correct answer)
- Amanda
- Bacula
- rsnapshot
Correct answer: Relax-and-Recover (ReaR)
ReaR (Relax-and-Recover) creates system configuration backups and bootable rescue media enabling complete bare metal disaster recovery on Linux.
Question 3: A differential backup strategy is used. Sunday is a full backup; Tuesday's differential is corrupt. Which backups are needed to restore to Wednesday?
- Sunday full + Wednesday differential (Correct answer)
- Sunday full + Tuesday differential + Wednesday differential
- Wednesday differential only
- Sunday full + all incrementals Mon-Wed
Correct answer: Sunday full + Wednesday differential
Differential backups always include all changes since the last full backup, so Wednesday's differential plus Sunday's full backup is sufficient regardless of Tuesday.
Question 4: What is the function of the '--link-dest' option in rsync?
- Create hard links to unchanged files from a previous backup, saving disk space (Correct answer)
- Create symbolic links to the backup source
- Link two remote rsync daemons together
- Set the destination directory for the backup
Correct answer: Create hard links to unchanged files from a previous backup, saving disk space
--link-dest causes rsync to hard-link files that are unchanged from a reference directory, enabling space-efficient snapshot-style backups.
Question 5: Which command verifies the integrity of an ext4 filesystem and is typically run only when the filesystem is unmounted?
- fsck.ext4 (Correct answer)
- e2image
- tune2fs
- debugfs
Correct answer: fsck.ext4
fsck.ext4 checks and repairs an ext4 filesystem for errors; it must be run on an unmounted filesystem to avoid data corruption.
Question 6: In Bacula, which daemon manages job scheduling, client catalog, and coordinates the overall backup/restore process?
- Director (bacula-dir) (Correct answer)
- File Daemon (bacula-fd)
- Storage Daemon (bacula-sd)
- Console (bconsole)
Correct answer: Director (bacula-dir)
The Bacula Director (bacula-dir) is the central control daemon that schedules jobs, maintains the catalog, and coordinates all backup and restore operations.
Question 7: Which command would verify that a gzip-compressed tar backup file is not corrupted without extracting it?
- tar -tzf backup.tar.gz > /dev/null
- gzip -t backup.tar.gz && tar -tf backup.tar.gz (Correct answer)
- tar -xzf backup.tar.gz --test
- gunzip --verify backup.tar.gz
Correct answer: gzip -t backup.tar.gz && tar -tf backup.tar.gz
gzip -t tests the compressed file's integrity, and tar -tf lists the archive contents (reading all data); together they verify both compression and archive structure.
LCA Backup & Disaster Recovery 5
What does 'bare metal recovery' refer to in disaster recovery?