EX200 Configure local storage Practice Test 5 — 15 Questions

Question 1

Which THREE of the following are valid steps to create and mount an XFS filesystem on a new disk /dev/sdb?

Accepted Answer

mount -t xfs /dev/sdb1 /mnt. The `mount -t xfs /dev/sdb1 /mnt` command explicitly specifies the XFS filesystem type with the `-t xfs` flag, ensuring the kernel uses the correct XFS driver to mount the filesystem. This is necessary when the filesystem type is not automatically detected or when you want to be explicit, which is a common requirement in exam scenarios.

Answer

mkfs.xfs -f /dev/sdb

Answer

mount /dev/sdb1 /mnt

Question 2

A system administrator runs the following command: # vgextend mydata-vg /dev/sdc. After successfully extending the volume group, what is the next step to make the additional space available in the logical volume mydata-lv?

Accepted Answer

lvextend -l +100%FREE /dev/mydata-vg/mydata-lv. After extending the volume group with vgextend, you must extend the logical volume to use the new free space. The command lvextend -l +100%FREE /dev/mydata-vg/mydata-lv allocates all remaining free extents in the volume group to the logical volume, making the additional space available for the filesystem.

Answer

xfs_growfs /data

Answer

resize2fs /dev/mydata-vg/mydata-lv

Answer

lvextend -L +10G /dev/mydata-vg/mydata-lv

Question 3

A system administrator is managing a Red Hat Enterprise Linux 9 server that uses LVM for storage. The volume group 'vgdata' contains two 500 GB physical volumes (sdb and sdc) with a logical volume 'lvdata' of 800 GB formatted with XFS and mounted at /data. The administrator adds a new 200 GB disk /dev/sdd and intends to use all of its capacity to extend lvdata. The following commands are executed in order: pvcreate /dev/sdd, vgextend vgdata /dev/sdd, lvextend -l +100%FREE /dev/vgdata/lvdata. The lvextend command completes successfully, but running 'df -h /data' still shows 800 GB. What is the most likely reason?

Accepted Answer

The filesystem has not been grown after extending the logical volume.. After extending the logical volume with `lvextend`, the underlying block device has more space, but the filesystem still sees the original size. For XFS, you must run `xfs_growfs /data` (or `xfs_growfs /dev/vgdata/lvdata`) to expand the filesystem to use the newly allocated extents. Without this step, `df -h` continues to report the old filesystem size.

Answer

The volume group 'vgdata' is not active, so the new space is ignored.

Answer

The logical volume was extended using a snapshot instead of the original.

Answer

The physical volume was not created correctly and the space is not available.

Question 4

Refer to the exhibit. An administrator wants to create a logical volume named 'data' of size 5GB in volume group 'myvg' and mount it at /data. What is the correct sequence of commands?

Accepted Answer

lvcreate -n data -L 5G myvg
mkfs.xfs /dev/myvg/data
mkdir /data
mount /dev/myvg/data /data
echo '/dev/myvg/data /data xfs defaults 0 0' >> /etc/fstab

Answer

vgcreate myvg /dev/sdb /dev/sdc
lvcreate -n data -L 5G myvg
mkfs.ext4 /dev/myvg/data
mount /dev/myvg/data /data

Answer

lvcreate -n data -L 5G myvg
mkfs.xfs /dev/myvg/data
mount /dev/myvg/data /data

Answer

pvcreate /dev/sdb
vgcreate myvg /dev/sdb
lvcreate -n data -L 5G myvg
mkfs.xfs /dev/myvg/data
mount /dev/myvg/data /data
echo '/dev/myvg/data /data ext4 defaults 0 0' >> /etc/fstab

Question 5

Refer to the exhibit. An administrator runs 'mount -o remount,ro /data' and then 'mount' shows /data as read-only. Later, the system is rebooted. What is the state of /data after reboot?

Accepted Answer

/data will be mounted read-write because fstab specifies defaults (rw).. The `mount -o remount,ro /data` command changes the mount state only for the current session; it does not modify the `/etc/fstab` entry. The `defaults` mount option in fstab implies `rw` (read-write). After a reboot, the system reads fstab and mounts `/data` according to its persistent configuration, which is read-write.

Answer

/data will be mounted read-only because the remount persists across reboots.

Answer

/data will not be mounted because the filesystem is marked as read-only.

Answer

/data will be mounted read-only because the kernel remembers the last mount state.

Question 6

Refer to the exhibit. After extending the logical volume, why does the df output still show 5.0G?

Accepted Answer

The filesystem needs to be resized with xfs_growfs.. The output shows the logical volume was extended (e.g., from 5G to 10G), but the filesystem itself has not been resized to use the new space. For XFS filesystems, the `xfs_growfs` command must be run to expand the filesystem to match the logical volume size. The `df` command reports filesystem usage, not block device size, so it still shows 5.0G until the filesystem is grown.

Answer

The lvextend command failed silently.

Answer

The filesystem type is ext4 and requires resize2fs.

Answer

The mount point /data is not accessible.

Question 7

Refer to the exhibit. After re-adding the disk, the recovery process shows 0% progress and remains at 0. What is the most likely cause?

Accepted Answer

The device /dev/sdb1 was not properly removed; it still holds old metadata that conflicts.. When a disk is re-added to a RAID array without first being properly removed (e.g., no mdadm --remove), it retains old superblock metadata. This conflicting metadata prevents mdadm from automatically starting the resync, leaving recovery at 0%. Clearing the superblock with mdadm --zero-superblock and then adding the disk as a new device will allow recovery to proceed.

Answer

The array is in a degraded state and the recovery is waiting for the resync to start, but the event count is zero; the array may need to be forced to start recovery.

Answer

The recovery is complete because the data is already synchronized.

Answer

The new disk /dev/sdb1 has a different size than the original, causing the recovery to stall.

Question 8

Refer to the exhibit. An administrator attempts to mount all filesystems using 'mount -a' and receives an error. What is the most likely cause?

Accepted Answer

The entry for /dev/vdb1 in /etc/fstab uses a device name that does not exist.. The error occurs because the entry in /etc/fstab for /dev/vdb1 references a device name that does not exist on the system. When 'mount -a' is executed, it reads /etc/fstab and attempts to mount each filesystem; if the device node is missing (e.g., due to a typo, incorrect kernel name, or the device not being attached), the mount fails with an error like 'mount: special device /dev/vdb1 does not exist'. This is the most likely cause given the scenario.

Answer

The ext4 filesystem on /dev/vdb1 is corrupted.

Answer

The filesystem type specified in /etc/fstab is incorrect.

Answer

The mount point /mnt/data does not exist.

Question 9

Refer to the exhibit. An administrator wants to create a RAID 1 array using /dev/sdb and /dev/sdc. Which of the following is true?

Accepted Answer

The administrator must create identical partition tables on both disks, such as a single Linux RAID partition, before creating the RAID array.. mdadm supports using whole disks as RAID components. The only real requirement is that the components have equal size, not that they have identical partition tables. Therefore, D's 'must' is false. The correct procedure is either to use both whole disks or create a Linux RAID partition on each, but it is not strictly required.

Answer

Both disks have a valid partition table and can be used directly for RAID.

Answer

/dev/sdb has no partitions and /dev/sdc has a partition; the administrator must remove the partition on /dev/sdc before creating RAID.

Answer

The administrator can create a RAID 1 array using the whole /dev/sdb and the partition /dev/sdc1 without any changes.

Question 10

Refer to the exhibit. An administrator tries to initialize /dev/sdb as an LVM physical volume but gets an error. What is the most likely cause?

Accepted Answer

The /etc/lvm/lvm.conf filter is set to exclude /dev/sdb.. The question says 'Refer to the exhibit' but no exhibit is included. The answer could depend on the error message shown (e.g., whether it mentions filtering or not). Without the exhibit, the student cannot reliably select an answer, and the marked correct answer cannot be fully justified.

Answer

The device /dev/sdb has a filesystem on it.

Answer

The device /dev/sdb does not exist.

Answer

The device /dev/sdb is already in use by another volume group.

Question 11

An administrator needs to ensure that a specific LVM logical volume is automatically mounted at boot with the 'noexec' option. Which configuration file and entry should be used?

Accepted Answer

/etc/fstab: /dev/vg/lv /mnt ext4 defaults,noexec 0 0. /etc/fstab is the standard configuration file for defining filesystem mount points and options that are applied automatically at boot. The entry specifies the logical volume device, mount point, filesystem type, and mount options including 'noexec' to prevent execution of binaries on that filesystem. The 'defaults' keyword ensures standard mount behavior is applied before the 'noexec' option overrides the exec permission.

Answer

/etc/fstab: /dev/vg/lv /mnt ext4 noexec 0 0

Answer

/etc/rc.d/rc.local: mount /dev/vg/lv /mnt -o noexec

Answer

/etc/rc.local: mount -o noexec /dev/vg/lv /mnt

Question 12

A server has a software RAID 5 array /dev/md0. One of its disks fails. The administrator wants to replace it without rebooting. Which command should be used to mark the disk as failed?

Accepted Answer

mdadm --fail /dev/md0 /dev/sdb. The correct command to mark a disk as failed in a software RAID array without rebooting is `mdadm --fail /dev/md0 /dev/sdb`. This command tells the md driver to mark the specified disk as faulty, which triggers the RAID 5 array to degrade and allows the failed disk to be removed and replaced while the system remains online.

Answer

mdadm --fault /dev/md0 /dev/sdb

Answer

echo faulty > /sys/block/md0/md/dev-sdb/state

Answer

mdadm --set-faulty /dev/md0 /dev/sdb

Question 13

An administrator wants to add the two 2G disks (sdc and sdd) as physical volumes, extend the 'data' logical volume in volume group 'vg' by 2G, and grow the filesystem. Which sequence of commands should be used?

Accepted Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc /dev/sdd; lvextend -L +2G /dev/vg/lv_data; xfs_growfs /data. It follows the correct sequence: create physical volumes on both disks, extend the volume group with both disks in a single command, extend the logical volume by exactly 2G using the `+` sign, and then grow the XFS filesystem using `xfs_growfs` with the mount point `/data`. The `+` in `lvextend -L +2G` is critical to add 2G rather than resize to 2G total, and `xfs_growfs` requires the mount point (or a block device) for XFS filesystems.

Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc /dev/sdd; lvresize -L 2G /dev/vg/lv_data; xfs_growfs /data

Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc /dev/sdd; lvextend -L +2G /dev/vg/lv_data; resize2fs /dev/vg/lv_data

Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc; vgextend vg /dev/sdd; lvextend -L +2G /dev/vg/lv_data; xfs_growfs /dev/vg/lv_data

Question 14

A system administrator is setting up storage for a new application server. The application requires two separate filesystems: one for the database (needs to be at least 10GiB) and one for logs (needs at least 5GiB). The server has a single 20GiB disk /dev/sda. The administrator plans to use LVM and a single volume group 'vg_app'. They create physical volume on /dev/sda, create the volume group, and then create two logical volumes: 'lv_db' of 10GiB and 'lv_logs' of 5GiB. They format lv_db as ext4 and lv_logs as xfs, and mount them at /db and /logs respectively. After rebooting, the system fails to mount /logs. What is the most likely cause?

Accepted Answer

The /logs entry is missing from /etc/fstab.. The most likely cause is that the /logs entry is missing from /etc/fstab. After reboot, the system relies on /etc/fstab to mount filesystems automatically. Since the administrator created and mounted the filesystem manually, but did not add an entry for /logs in /etc/fstab, the mount fails on reboot. The database mount may succeed if it was added, but the logs mount fails due to the missing fstab entry.

Answer

The logical volume 'lv_logs' overlaps with 'lv_db'.

Answer

The physical volume /dev/sda is not recognized by LVM after reboot.

Answer

The volume group 'vg_app' is not automatically activated.

Question 15

Which command can be used to create a logical volume using all available free space in a volume group?

Accepted Answer

lvcreate -l 100%FREE -n lvdata vgdata. The `-l 100%FREE` flag allocates all unallocated physical extents in the volume group, which is the precise way to use all available free space. Option D (`-l 100%VG`) is incorrect because it attempts to allocate 100% of the volume group's extents, including those already used by other logical volumes, causing the command to fail if any extents are already allocated. Therefore, only option B is correct.

Answer

lvcreate --size 20G vgdata lvdata

Answer

lvcreate -L 20G -n lvdata vgdata

Answer

lvcreate -l 100%VG -n lvdata vgdata

Answer

lvcreate -L 100%FREE -n lvdata vgdata