Chapter 5: Linux Filesystem Administration

/etc/fstab

A file used to specify which filesystems to mount automatically at boot time and queried by the mount command if an insufficient number of arguments are specified.

Physical Volumes (PVs)

A hard disk partition that is used by the LVM.

soft limit

A hard disk quota that the user can exceed for a certain period of time.

hard limit

A hard disk quota that the user cannot be exceed.

partition

A physical division of a hard disk drive. physical extent (PE) size The block size used by the LVM when storing data on a volume group.

mounting

A process used to associate a device with a directory in the logical directory tree such that users can store data on that device.

cylinder

A series of tracks on a hard disk that are written to simultaneously by the magnetic heads in a hard disk drive.

Logical Volume Manager (LVM)

A set of software components within Linux that can be used to manage the storage of information across several different hard disks on a Linux system.

/, /dev/pts, /dev/shm

Given the following output from /etc/fstab, which filesystems will be automatically checked on boot by the fsck command? /dev/sda1 / ext4 defaults 1 1 none /dev/pts devpts gid=5,mode=620 1 0 none /proc proc defaults 0 1 none /dev/shm tmpfs defaults 1 0 /dev/sdc2 swap swap defaults 0 1 /dev/dvd /media/dvd iso9660 noauto,ro 0 0

True

Two different SATA devices might share the same major # as they use the same driver in Linux.

displays the number of used and available inodes for an ext2/ext3/ext4 filesystem

What does the command dumpe2fs -h do? backs up an ext2 filesystem displays the number of used and available inodes for an ext2/ext3/ext4 filesystem dumps an ext2 filesystem nothing; it is not a valid command

displays the total size of the /var directory du /var = shows size of all directories within the /var directory

What does the du -s /var command do? shows the users connected to the /var directory shows the size of all directories within the /var directory dumps the /var directory displays the total size of the /var directory

Unmount the filesystem.

What must you do to successfully run the fsck command on a filesystem?

xfs_repair /dev/sdb1

Which command can be used to repair an XFS filesystem? fsck -t xfs /dev/sdb1 e2fsck /dev/sdb1 fsck.xfs /dev/sdb1 xfs_repair /dev/sdb1

parted

Which of the following commands can be used to create partitions on either a MBR or GPT hard disk? a. parted b. gdisk c. fdisk d. cdskck

gdisk

Which of the following commands can only be used to create partitions on a GPT hard disk? gdisk cfdisk fdisk parted

VGs are comprised of one or more PVs

Which of the following statements regarding LVM structure is correct? PVs are collections of VGs LVs are created from the free space available within PVs VGs are comprised of one or more PVs PVs use the space within LVs to create VGs

df (disk free space) command

A command that displays disk free space by filesystem.

quotaon command

A command used to activate disk quotas.

vgextend command

A command used to add additional physical volumes to an LVM VG.

lvextend command

A command used to add additional space from VGs to existing LVM

umount command

A command used to break the association between a device and a directory in the logical directory tree.

btrfs command

A command used to configure btrfs filesystem options and check btrfs filesystems for errors.

vgcreate command

A command used to create LVM VG.

lvcreate command

A command used to create LVM logical volumes.

pvcreate command

A command used to create LVM physical volumes.

mkisofs command

A command used to create an ISO image from one or more files on the filesystem.

gdisk (GPT fdisk) command

A command used to create partitions on a GPT hard disk. It uses an interface that is very similar to fdisk.

parted (GNU Parted) command

A command used to create partitions on a GPT or MBR hard disk.

swapoff command

A command used to disable a partition for use as virtual memory on the Linux system.

swapon command

A command used to enable a partition for use as virtual memory on the Linux system.

mkfs (make filesystem) command

A command used to format or create filesystems.

fuser command

A command used to identify any users or processes using a particular file or directory.

tune2fs command

A command used to modify ext2 and ext3 filesystem parameters.

mount command

A command used to mount filesystems on devices to mount point directories.

cfdisk command

A command used to partition hard disks; displays a graphical interface in which the user can select partitioning options.

mkswap command

A command used to prepare newly created swap partitions for use by the Linux system.

repquota command

A command used to produce a report on quotas for a particular filesystem.

mknod command

A command used to re-create a device file, provided the major number, minor number, and type (character or bock) are known.

edquota command

A command used to specify quota limits for users and groups.

vgdisplay command

A command used to view LVM VG.

vgscan command

A command used to view LVM VGs.

lvdisplay command

A command used to view LVM logical volumes.

lvscan command

A command used to view LVM logical volumes.

pvdisplay command

A command used to view LVM physical volumes.

pvscan command

A command used to view LVM physical volumes.

quota command

A command used to view disk quotas imposed on a user.

has no data section displays a major and minor number in place of a file size

A device file _______________________. (Choose all that apply.) has no inode section has no data section displays a major and minor number in place of a file size has a fixed size of 300 kilobytes

/etc/mtab

A file that stores a list of currently mounted filesystems.

device file

A file used by Linux commands that represents a specific device on the system; these files do not have a data section and use major and minor numbers to reference the proper driver and specific device on the system, respectively.

du (directory usage) command

A command that displays directory usage.

fdisk command

A command used to create, delete, and manipulate partitions on hard disks.

quotaoff command

A command used to deactivate disk quotas.

/proc/devices

A file that contains currently used device information.

Volume Group (VG)

A group of PVs that are used by the LVM.

false

After a partition on a hard disk is formatted with a filesystem, all partitions on that hard disk drive must use the same filesystem. True or False?

False

Character devices typically transfer data more quickly than block devices. True or False?

True

Device nodes consist of inodes and no data blocks? As a result the total contents of device directory is 0 kilobytes

/dev/tty1

First local terminal on the system (ctrl + alt + F1) Second local terminal on the system (ctrl + alt + F2)

/dev/loop0

First loop back interface

/dev/sr0

First writable SATA CD or DVD device in the system.

bad blocks

The areas of a storage medium unable to store data properly.

mount point

The directory in a file structure to which something is mounted.

/dev/sda1

First partition on the first SATA/SCSI/SAS hard disk or SSD Block device

/dev/ttyS0

First serial port on system (COM1)

displays c or b in ls -l type column. ex: brw-rw - - - - 1 root disk 8, 1 Feb 23 16:02 /dev/sdal

How are block & character devices represented in long detail list command?

True

The lvextend command can be used to add unused space within a volume group to an existing logical volume. True or False?

major number

The number used by the kernel to identify which device driver to call to interact properly with a given category of hardware; hard disk drives, CDs, and video cards are all categories of hardware; similar devices share a common major number.

filesystem

The organization imposed on a physical storage medium that is used to manage the storage and retrieval of data.

formatting

The process in which a filesystem is placed on a disk device. fsck (filesystem check) command A command used to check the integrity of a filesystem and repair damaged files.

syncing

The process of writing data to the hard disk drive that was stored in RAM.

block

The unit of data commonly used by filesystem commands; a block can contain several sectors.

e2mkfs -t ext4 device mke2fs -t ext4 device

Which command is used to format a partition on a hard disk drive with the ext4 filesystem? format_ext4 device ext4mkfs device e2mkfs -t ext4 device makeext4FS device

mount -a

Which command mounts all existing filesystems in /etc/fstab? mount -f mount -a mount /etc/fstab mount /etc/mtab

Quotas can limit both user space and the number of files a user can own. Hard limits can never be exceeded. Soft limits allow a user to exceed them for a certain period of time.

Which of the following statements are true? (Choose all that apply.) Quotas can only limit user space. Quotas can only limit the number of files a user can own. Quotas can limit both user space and the number of files a user can own. Hard limits can never be exceeded. Hard limits allow a user to exceed them for a certain period of time. Soft limits can never be exceeded. Soft limits allow a user to exceed them for a certain period of time. Either a hard limit or a soft limit can be set, but not both concurrently.

/dev/sdc1

You plug a USB flash memory drive into a system that has two SATA hard disks. How will the partition on this USB flash memory drive be identified by Linux? /dev/sda1 /dev/sda2 /dev/sdb1 /dev/sdc1

c. cat /etc/mtab

You want to see the filesystems that are presently in use on the system. What command could you use? a. cat /etc/fstab b. ls -l /etc/fstab c. cat /etc/mtab d. ls -l /etc/fstab

Major # points to device driver

ls -l /dev/sdb /dev/sdb1 /dev/sdb2 brw-rw- - - - 1 root disk 8, ... brw-rw- - - - 1 root disk 8, ... brw-rw- - - - 1 root disk 8, ...

Unmount the device from the directory.

A user mounts a device to a mount point directory and realizes afterward she needs files previously found within the mount point directory. What should this user do? Nothing; the files are lost and cannot ever be accessed. Nothing; the files could not have been there because you can only mount to empty directories. Unmount the device from the directory. Run the fsck command to recover the file. Look in the lost+found directory for the file.

Mount the filesystem and check the lost+found directory underneath the mount point

A user runs the fsck command with the -f option on an ext4 filesystem that is showing signs of corruption. How would that user locate any files the system was unable to repair? Look in the root of the filesystem. The system prompts the user for a target location when it comes across a file it cannot repair. Mount the filesystem and check the lost+found directory underneath the mount point. View the contents of the directory /lost+found.

Logical Volume (LV)

A volume that is managed by the LVM and comprised of free space within a VG.

/dev/hda1

First partition on the first PATA hard disk or SSD (primary master) Block device

/dev/nvme0n1p1

First partition on the first namespace hard disk on the first NVMe SSD Block device

/dev/hdd1

First partition on the fourth PATA hard disk or SSD (primary master)

/devhbd1

First partition on the second PATA hard disk or SSD (primary master) Block device

/dev/sdb1

First partition on the second SATA/SCSI/SAS hard disk or SSD Block device

/dev/hcd1

First partition on the third PATA hard disk or SSD (primary master) Block device

Use the fdisk command to create one or more partitions on each of the hard disk drives mount any partitions created on the two hard drives so that they are accessible by the operating system Format any partitions created with a valid filesystem recognized by Linux (FROM TEST Mount any partitions created on the two hard drives such that they are accessible by the operating system)

Jim has just installed two new SAS SSDs in his system. He properly installs the hardware in his machine. Before he can use them for data storage and retrieval, what must he do? (Choose all that apply.) Mount the two SSDs so they are accessible by the operating system. Mount a filesystem to each of SSDs. Create one or more partitions on each of the SSDs. Use the vi editor to edit /etc/mtab and create an entry for the SSDs. Mount any partitions created on the two SSDs such that they are accessible by the operating system. Format any partitions created on the SSDs with a valid filesystem recognized by Linux.

track

The area on a hard disk that forms a concentric circle of sectors.

/dev directory

The directory off the root where device files are typically stored.

filesystem corruption

The errors in a filesystem structure that prevent the retrieval of stored data.

root filesystem

The filesystem that contains most files that make up the operating system; it should have enough free space to prevent errors and slow performance.

a. The device file has become corrupt.

The first floppy drive on the system is not responding. You enter the file /dev/fd0 command and receive the following output. What is the problem? [root@server1 root]# file /dev/fd0/dev/fd0: ASCII text[root@server1 root]# a. The device file has become corrupt. b. The floppy drive is seen as a character device. c. There is no floppy disk in the drive. d. The floppy drive cable has come loose.

hard disk quotas

The limits on the number of files, or total storage space on a hard disk drive, available to a user.

quotas

The limits that can be imposed on users and groups for filesystem usage.

minor number

The number used by the kernel to identify which specific hardware device, within a given category, to use a driver to communicate with. See also major number.

sector

The smallest unit of data storage on a hard disk; sectors are arranged into concentric circles called tracks and can be grouped into blocks for use by the system.

block devices

The storage devices that transfer data to and from the system in chunks of many data bits by caching the information in RAM; they are represented by block device files.

character devices

The storage devices that transfer data to and from the system one data bit at a time; they are represented by character device files.

Minor # indicates the particular device itself addition devices (partitions) minor numbers are in increments of 16

ls -l /dev/sda /dev/sda1 /dev/sda2 ... 0 Feb 23 16:02 /dev/sda ... 1 Feb 23 16:02/dev/sda1 ... 2 Feb 23 16:02 /dev/sda2 ... 3 Feb 23 16:02/dev/sda13 ls -l /dev/sdb /dev/sdb1 /dev/sdb2 brw-rw- - - - 1 root disk 8, 16 Feb 23 16:02 /dev/sdb