RHCSA Series (6): Controlling Filesystems
RHCSA_Series_6_Mind_Map
│
├── Alphabetical_List_of_Abbreviations
│ ├── Btrfs = B-Tree File System
│ ├── cfdisk = Compact Flash Disk
│ ├── df = Disk Free
│ ├── du = Disk Usage
│ ├── e2label = Ext2 File System Label
│ ├── ext2 = Ext2 File System
│ ├── ext3 = Ext3 File System
│ ├── ext4 = Ext4 File System
│ ├── fsck = File System Check
│ ├── fstab = File System Table
│ ├── JFS = Journaling File System
│ ├── LVM = Logical Volume Manager
│ ├── LVs = Logical Volumes
│ ├── mdadm = Multiple Disk Administrator
│ ├── mkfs = Make File System
│ ├── MBR = Master Boot Record
│ ├── NTFS = New Technology File System
│ ├── PVs = Physical Volumes
│ ├── RAID = Redundant Array of Independent Disks
│ ├── RHCSA = Red Hat Certified System Administrator
│ ├── SSD = Solid-State Drive
│ ├── sysdig = System Dig
│ ├── tune2fs = Tune Ext2 File System
│ ├── UUID = Universally Unique Identifier
│ ├── VGs = Volume Groups
│ ├── vmstat = Virtual Memory Statistics
│ └── XFS = X File System
│
├── The_Fundamentals_of_GNU/Linux_Filesystems
│ ├── Directory_Structure: /, /home, /boot, /var
│ ├── Filesystem_Types: Ext2, Ext3, Ext4, XFS, Btrfs
│ ├── Filesystem_Creation_and_Mounting: mkfs, mount, umount, fstab
│ ├── Filesystem_Maintenance: fsck, journaling, tune2fs, e2label
│ ├── Disk_Quotas
│ └── Advanced_Concepts: RAID, LVM
│
├── Mounting_and_Unmounting_GNU/Linux_Filesystems
│ ├── mount_and_umount_Commands
│ ├── fstab_Configuration
│ ├── Mount_Options: ro, rw, noatime, nodiratime
│ ├── Filesystem_Types: ext2, ext3, ext4, xfs, btrfs
│ └── Automounting_with_autofs
│
├── GNU/Linux_Disk_Partitioning
│ ├── Partitioning_Tools: fdisk, parted, cfdisk
│ ├── Partition_Types: Primary, Extended, Logical, Linux, Swap, FAT, NTFS
│ ├── Disk_Labels: UUID
│ ├── Backup_and_Naming_Best_Practices
│ └── Logical_Volume_Management_(LVM)
│
├── Optimizing_GNU/Linux_Filesystem_Performance
│ ├── Filesystem_Selection
│ ├── Mount_Options: noatime, nodiratime, discard
│ ├── Disk_Tuning_Tools: tune2fs, xfs_admin
│ ├── Performance_Monitoring_Tools: iostat, vmstat, sysdig
│ ├── Caching_Mechanisms: page_cache, directory_entry_cache, tmpfs, ramfs
│ └── Storage_Pooling: LVM, RAID
│
├── GNU/Linux_Filesystem_Tunable_Parameters
│ ├── Mount_Options
│ ├── tune2fs_and_xfs_admin_Usage
│ ├── Filesystem_Features: journaling, extents, quota
│ └── Kernel_Parameters: disk_queue_depth, scheduler
│
├── Checking_GNU/Linux_Filesystem_Status
│ ├── Status_Tools: df, du, fsck, tune2fs
│ ├── Filesystem_Health_Checking
│ ├── Types_of_Checks: Read-Only, Read-Write, Automatic
│ └── Logging_and_Event_Tracking
│
├── Understanding_GNU/Linux_Journaling_Filesystems
│ ├── Journaling_Filesystems: ext3, ext4, XFS, JFS
│ ├── Journaling_Modes: data=journal, data=ordered, data=writeback
│ ├── Journal_Size_Configuration
│ ├── Benefits_of_Journaling
│ ├── Journal_Recovery
│ └── Journaling_Tuning
│
└── GNU/Linux_Filesystem_Topics:_RAID_and_LVM
├── RAID_Configurations: RAID_0, RAID_1, RAID_5, RAID_6
├── RAID_Levels
├── LVM_Components: PVs, VGs, LVs
├── LVM_Operations: create, resize, remove, move
├── Benefits_of_RAID_and_LVM
└── Troubleshooting_RAID_and_LVM
Alphabetical List of the Abbreviations used in this article:
Btrfs = B-Tree File System
cfdisk = Compact Flash Disk
df = Disk Free
du = Disk Usage
e2label = Ext2 File System Label
ext2 = Ext2 File System
ext3 = Ext3 File System
ext4 = Ext4 File System
fsck = File System Check
fstab = File System Table
JFS = Journaling File System
LVM = Logical Volume Manager
LVs = Logical Volumes
mdadm = Multiple Disk Administrator
mkfs = Make File System
MBR = Master Boot Record
NTFS = New Technology File System
PVs = Physical Volumes
RAID = Redundant Array of Independent Disks
RHCSA = Red Hat Certified System Administrator
SSD = Solid-State Drive
sysdig = System Dig
tune2fs = Tune Ext2 File System
UUID = Universally Unique Identifier
VGs = Volume Groups
vmstat = Virtual Memory Statistics
XFS = X File System
Executive Summary
As a Red Hat Certified System Administrator (RHCSA), understanding and effectively managing file systems is crucial for ensuring the smooth operation of Red Hat-based systems. To achieve this, it is essential to have a solid grasp of the fundamentals of GNU/Linux file systems, including the structure of the root, home, boot, and var directories, as well as common file system types such as Ext2, Ext3, Ext4, XFS, and Btrfs.
In addition to understanding file system basics, administrators must also be knowledgeable about file system mounting, including how to manually mount and unmount file systems using the mount and umount commands, as well as configuring automounting with autofs. Furthermore, familiarity with disk partitioning tools like fdisk, parted, and cfdisk is necessary, along with the ability to create, format, label, and resize file systems using tools such as mkfs, mkdir, e2label, and resize2fs or xfs_growfs.
To optimize file system performance, administrators must understand tuneable parameters for various file system types, including mount options for Ext4, XFS, and Btrfs. They must also be able to check the file system status using commands such as df, du, and fsck, and optimize performance using tools like tunefs for Ext4 or btrfs fi tune for Btrfs. Additionally, a solid understanding of journaling file systems, including their purpose, advantages, and the difference between journals and superblocks, is essential.
Advanced topics such as RAID and LVM are also critical components of file system management. Administrators must understand RAID concepts, levels, benefits, and limitations, and be able to configure software-based RAID using mdadm. They must also be familiar with the concept of LVM, its benefits, and how it differs from traditional partitioning, and be able to create, resize, move, and delete logical volumes using LVM tools like pvcreate, vgcreate, lvcreate, lvextend, and vgreduce. By mastering these concepts, Red Hat Certified System Administrators can ensure effective and efficient management of file systems in Red Hat-based GNU/Linux distributions.
How I Used Reference 1 in This Article:
Reference 1 cited many features that make up GNU/Linux and other computer operating systems. The fifth of these features is "controlling filesystems". This fifth feature will be the 100% focus of this article.
Credits
The folllowing research assistants were invaluable tools that allowed me to complete this article in a timely manner: Mistral (an open-source local large language model - LLM) and HuggingChat (an online portal to about a dozen open source LLMs).
The Fundamentals of GNU/Linux Filesystems
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of the fundamentals of GNU/Linux filesystems. This includes knowledge of the structure of Linux filesystems, including the root `/` directory, which is the top-most directory in the filesystem hierarchy, as well as the `home` `/home` directory, where user data is stored, the `boot` `/boot` directory, which contains the kernel and boot loader configuration files, and the `var` `/var` directory, which stores variable data such as logs and spool files.
In addition to understanding the directory structure, RHCSA candidates should be familiar with the different types of filesystems available in Linux, including `Ext2`, `Ext3`, `Ext4`, `XFS`, and `Btrfs`. Each of these filesystems has its own strengths and weaknesses, and understanding their characteristics is crucial for making informed decisions about which filesystem to use in a given situation. For example, `Ext4` is a widely used filesystem that offers a good balance between performance and reliability, while `XFS` is a high-performance filesystem that is well-suited for large storage systems.
RHCSA candidates should also understand how to work with filesystems, including how to create, mount, and unmount them. This includes using commands such as `mkfs` to create a new filesystem, `mount` to attach a filesystem to a directory, and `umount` to detach a filesystem from a directory. Additionally, candidates should be familiar with the concept of `fstab`, which is a file that contains information about the filesystems on a system, including their mount points and options. Understanding how to edit `fstab` is essential for configuring filesystems to mount automatically at boot time.
Filesystem maintenance is another critical aspect of RHCSA knowledge. This includes understanding how to check the integrity of a filesystem using commands such as `fsck`, as well as how to repair a damaged filesystem. Candidates should also be familiar with the concept of journaling, which is a technique used by some filesystems to improve reliability and performance. Journaling filesystems, such as `Ext3` and `Ext4`, use a `journal` to keep track of changes made to the filesystem, which allows for faster recovery in the event of a crash or power failure.
In terms of filesystem performance, RHCSA candidates should understand how to optimize filesystems for optimal performance. This includes understanding how to use commands such as `tune2fs` to adjust filesystem parameters, such as the block size and inode size, as well as how to use commands such as `e2label` to change the label of a filesystem. Candidates should also be familiar with the concept of disk quotas, which allow administrators to limit the amount of disk space available to users or groups. Understanding how to configure and manage disk quotas is essential for preventing disk space from becoming too full, which can cause system performance to degrade.
Finally, RHCSA candidates should be familiar with advanced filesystem concepts, such as `RAID` and `LVM`. `RAID` stands for Redundant Array of Independent Disks, and is a technique used to combine multiple disks into a single logical disk, which can improve performance and reliability. `LVM` stands for Logical Volume Manager, and is a system that allows administrators to manage disk space in a flexible and efficient way. Understanding how to configure and manage `RAID` and `LVM` systems is essential for building high-performance and highly available storage systems. By mastering these concepts, RHCSA candidates can demonstrate their expertise in managing and maintaining GNU/Linux filesystems, and can provide effective support for Linux systems in a variety of environments.
Mounting and Unmounting GNU/Linux Filesystems
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of mounting and unmounting GNU/Linux filesystems. Mounting a filesystem allows it to be accessed and used by the system, while unmounting it makes it unavailable. The `mount` command is used to mount a filesystem, and it requires the device file of the filesystem, the mount point, and any optional mount options. For example, to mount a filesystem located on the `/dev/sdb1` device to the `/mnt` directory, the command `mount /dev/sdb1 /mnt` would be used.
In addition to the `mount` command, RHCSA candidates should also be familiar with the `umount` command, which is used to unmount a filesystem. The `umount` command requires the mount point or the device file of the filesystem as an argument. For example, to unmount the filesystem mounted on the `/mnt` directory, the command `umount /mnt` would be used. It is also possible to use the `-a` option with the `umount` command to unmount all mounted filesystems, except for the root filesystem.
RHCSA candidates should also understand the concept of the `fstab` file, which is used to configure filesystems to mount automatically at boot time. The `fstab` file contains a list of filesystems, along with their mount points and options, and is used by the system to determine which filesystems to mount and how to mount them. Each line in the `fstab` file represents a single filesystem, and contains six fields: the device file, the mount point, the filesystem type, the mount options, the dump frequency, and the fsck pass number. Understanding how to edit the `fstab` file is essential for configuring filesystems to mount automatically at boot time.
In terms of mount options, RHCSA candidates should be familiar with the various options that can be used to customize the behavior of a mounted filesystem. For example, the `ro` option can be used to mount a filesystem read-only, while the `rw` option can be used to mount a filesystem read-write. Other options, such as `noatime` and `nodiratime`, can be used to disable the updating of access times and directory access times, respectively. Understanding how to use these options is essential for optimizing the performance and security of a GNU/Linux system.
Filesystem types are also an important consideration when mounting and unmounting filesystems. RHCSA candidates should be familiar with the various filesystem types that are supported by GNU/Linux, including `ext2`, `ext3`, `ext4`, `xfs`, and `btrfs`. Each of these filesystems has its own strengths and weaknesses, and understanding their characteristics is essential for making informed decisions about which filesystem to use in a given situation. For example, `ext4` is a widely used filesystem that offers a good balance between performance and reliability, while `xfs` is a high-performance filesystem that is well-suited for large storage systems.
Finally, RHCSA candidates should be familiar with the concept of automounting, which allows filesystems to be mounted automatically when they are accessed. Automounting can be configured using the `autofs` service, which uses a configuration file to determine which filesystems to mount and how to mount them. Understanding how to configure and manage automounting is essential for providing a convenient and user-friendly experience for system users. By mastering the concepts of mounting and unmounting GNU/Linux filesystems, RHCSA candidates can demonstrate their expertise in managing and maintaining GNU/Linux systems, and can provide effective support for Linux systems in a variety of environments.
GNU/Linux Disk Partitioning
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of GNU/Linux disk partitioning. Disk partitioning is the process of dividing a hard disk drive into separate partitions, each of which can be used to store a separate filesystem or other data. The most common partitioning tool used in GNU/Linux is `fdisk`, which is a command-line utility that allows administrators to create, delete, and modify disk partitions.
RHCSA candidates should be familiar with the different types of disk partitions that can be created using `fdisk`, including primary partitions, extended partitions, and logical partitions. Primary partitions are the main partitions on a disk, and can be used to store a filesystem or other data. Extended partitions are used to contain logical partitions, which are additional partitions that can be created beyond the four primary partitions allowed by the Master Boot Record (MBR) partitioning scheme. Logical partitions are used to store additional filesystems or data, and can be created within an extended partition.
In addition to `fdisk`, RHCSA candidates should also be familiar with other disk partitioning tools, such as `parted` and `cfdisk`. `parted` is a more advanced partitioning tool that allows administrators to create, delete, and modify disk partitions, as well as resize and move existing partitions. `cfdisk` is a menu-driven partitioning tool that provides a more user-friendly interface for creating and managing disk partitions.
When creating disk partitions, RHCSA candidates should be aware of the different partition types that can be used, including `Linux`, `Swap`, `FAT`, and `NTFS`. Each of these partition types has its own specific use case, and understanding their characteristics is essential for making informed decisions about which partition type to use in a given situation. For example, `Linux` partitions are used to store GNU/Linux filesystems, while `Swap` partitions are used to store virtual memory.
RHCSA candidates should also be familiar with the concept of disk labels, which are used to identify disk partitions and filesystems. The most common disk label used in GNU/Linux is the `UUID` (Universally Unique Identifier), which is a unique identifier assigned to each disk partition and filesystem. Understanding how to use disk labels is essential for managing and maintaining disk partitions and filesystems.
In terms of best practices, RHCSA candidates should be aware of the importance of backing up data before making any changes to disk partitions. This is because modifying disk partitions can potentially result in data loss, and having a backup of important data can help to prevent this. Additionally, RHCSA candidates should be aware of the importance of using a consistent naming convention for disk partitions and filesystems, as this can help to simplify management and maintenance tasks.
Finally, RHCSA candidates should be familiar with the concept of Logical Volume Management (LVM), which is a disk management system that allows administrators to create, manage, and maintain logical volumes. LVM provides a more flexible and scalable way of managing disk storage, and is widely used in enterprise environments. Understanding how to use LVM is essential for managing and maintaining complex disk storage systems, and is an important skill for any Red Hat Certified System Administrator.
Optimizing GNU/Linux Filesystem Performance
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of optimizing GNU/Linux filesystem performance. Filesystem performance is critical to the overall performance of a GNU/Linux system, and there are several techniques that can be used to optimize it. One of the most important factors in optimizing filesystem performance is the choice of filesystem type. Different filesystems have different performance characteristics, and choosing the right filesystem for a particular use case can make a significant difference in performance.
RHCSA candidates should be familiar with the different filesystem types available in GNU/Linux, including `ext2`, `ext3`, `ext4`, `xfs`, and `btrfs`. Each of these filesystems has its own strengths and weaknesses, and understanding their characteristics is essential for making informed decisions about which filesystem to use in a given situation. For example, `ext4` is a widely used filesystem that offers a good balance between performance and reliability, while `xfs` is a high-performance filesystem that is well-suited for large storage systems.
In addition to choosing the right filesystem type, RHCSA candidates should also be familiar with the various options that can be used to optimize filesystem performance. These options include `noatime`, `nodiratime`, and `discard`, which can be used to disable the updating of access times, directory access times, and to enable discard support for solid-state drives (SSDs). Understanding how to use these options is essential for optimizing filesystem performance, as they can help to reduce the number of disk I/O operations and improve overall system performance.
RHCSA candidates should also be familiar with the concept of disk tuning, which involves adjusting the parameters of a disk to optimize its performance. This can include adjusting the block size, the number of inodes, and the disk queue depth. Understanding how to use disk tuning tools, such as `tune2fs` and `xfs_admin`, is essential for optimizing disk performance and improving overall system performance.
In terms of monitoring and analyzing filesystem performance, RHCSA candidates should be familiar with the various tools that are available, including `iostat`, `vmstat`, and `sysdig`. These tools can be used to monitor disk I/O activity, memory usage, and system calls, and can help to identify performance bottlenecks and optimize system performance. Understanding how to use these tools is essential for identifying and resolving performance issues, and for optimizing overall system performance.
RHCSA candidates should also be familiar with the concept of caching, which involves storing frequently accessed data in memory to improve performance. GNU/Linux provides several caching mechanisms, including the page cache and the directory entry cache, which can be used to improve filesystem performance. Understanding how to use caching mechanisms, such as `tmpfs` and `ramfs`, is essential for optimizing filesystem performance and improving overall system performance.
Finally, RHCSA candidates should be familiar with the concept of storage pooling, which involves combining multiple storage devices into a single logical storage device. Storage pooling can be used to improve performance, increase capacity, and provide redundancy. Understanding how to use storage pooling technologies, such as LVM and RAID, is essential for optimizing storage performance and improving overall system performance. By mastering the techniques of optimizing GNU/Linux filesystem performance, RHCSA candidates can demonstrate their expertise in managing and maintaining high-performance GNU/Linux systems.
GNU/Linux Filesystem Tunable Parameters
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of GNU/Linux filesystem tunable parameters. Filesystem tunable parameters are settings that can be adjusted to optimize the performance and behavior of a filesystem. These parameters can be used to tune the filesystem for specific use cases, such as high-performance databases or large-scale file servers.
RHCSA candidates should be familiar with the different types of filesystem tunable parameters, including mount options, filesystem attributes, and kernel parameters. Mount options are settings that are specified when a filesystem is mounted, such as the `noatime` option, which disables the updating of access times. Filesystem attributes are settings that are stored on the filesystem itself, such as the `inode size` and `block size`. Kernel parameters are settings that are configured at the kernel level, such as the `disk queue depth` and `scheduler`.
One of the most important filesystem tunable parameters is the `mount option`. Mount options can be used to specify various settings, such as the filesystem type, the mount point, and the options to be used when mounting the filesystem. For example, the `noatime` option can be used to disable the updating of access times, while the `nodiratime` option can be used to disable the updating of directory access times. Understanding how to use mount options is essential for optimizing filesystem performance and behavior.
RHCSA candidates should also be familiar with the `tune2fs` command, which is used to adjust filesystem attributes, such as the `inode size` and `block size`. The `tune2fs` command can be used to optimize the filesystem for specific use cases, such as high-performance databases or large-scale file servers. For example, increasing the `inode size` can improve performance for filesystems with a large number of small files, while increasing the `block size` can improve performance for filesystems with a large number of large files.
In addition to `tune2fs`, RHCSA candidates should also be familiar with the `xfs_admin` command, which is used to adjust filesystem attributes for XFS filesystems. The `xfs_admin` command can be used to optimize the filesystem for specific use cases, such as high-performance databases or large-scale file servers. For example, increasing the `inode size` can improve performance for filesystems with a large number of small files, while increasing the `block size` can improve performance for filesystems with a large number of large files.
RHCSA candidates should also be familiar with the concept of `filesystem features`, which are settings that can be enabled or disabled to optimize the performance and behavior of a filesystem. Filesystem features can include settings such as `journaling`, `extents`, and `quota`. Understanding how to use filesystem features is essential for optimizing filesystem performance and behavior.
Finally, RHCSA candidates should be familiar with the concept of `kernel parameters`, which are settings that are configured at the kernel level. Kernel parameters can include settings such as the `disk queue depth` and `scheduler`, which can be used to optimize the performance of the filesystem. Understanding how to use kernel parameters is essential for optimizing filesystem performance and behavior. By mastering the concepts of GNU/Linux filesystem tunable parameters, RHCSA candidates can demonstrate their expertise in managing and maintaining high-performance GNU/Linux systems.
Checking GNU/Linux Filesystem Status
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of checking GNU/Linux filesystem status. Checking the status of a filesystem is crucial to ensure that it is healthy, functional, and performing optimally. There are several tools and commands that can be used to check the status of a GNU/Linux filesystem, including `df`, `du`, `fsck`, and `tune2fs`.
RHCSA candidates should be familiar with the `df` command, which is used to display information about the disk usage of a filesystem. The `df` command can be used to display the total size of a filesystem, the amount of used and available space, and the percentage of used space. For example, the command `df -h` can be used to display the disk usage of all filesystems in a human-readable format.
In addition to `df`, RHCSA candidates should also be familiar with the `du` command, which is used to estimate the disk usage of a directory or a set of files. The `du` command can be used to display the total size of a directory or a set of files, as well as the size of each individual file. For example, the command `du -sh /home` can be used to display the total size of the `/home` directory.
RHCSA candidates should also be familiar with the `fsck` command, which is used to check the integrity of a filesystem. The `fsck` command can be used to detect and repair errors on a filesystem, such as corrupted inodes, bad blocks, and inconsistent file system structures. For example, the command `fsck -y /dev/sda1` can be used to check the integrity of the `/dev/sda1` filesystem and automatically repair any errors that are found.
In addition to `fsck`, RHCSA candidates should also be familiar with the `tune2fs` command, which is used to display and adjust the parameters of an ext2, ext3, or ext4 filesystem. The `tune2fs` command can be used to display information about the filesystem, such as the block size, inode size, and volume name. For example, the command `tune2fs -l /dev/sda1` can be used to display the parameters of the `/dev/sda1` filesystem.
RHCSA candidates should also be familiar with the concept of `filesystem health`, which refers to the overall condition of a filesystem. Filesystem health can be affected by various factors, such as disk errors, corrupted files, and inconsistent file system structures. Understanding how to check and maintain filesystem health is essential for ensuring the reliability and performance of a GNU/Linux system.
In terms of checking filesystem status, RHCSA candidates should be familiar with the different types of checks that can be performed, including `read-only` checks, `read-write` checks, and `automatic` checks. Read-only checks are used to check the integrity of a filesystem without making any changes, while read-write checks are used to check the integrity of a filesystem and make any necessary repairs. Automatic checks are used to schedule regular checks of a filesystem to ensure that it remains healthy and functional.
Finally, RHCSA candidates should be familiar with the concept of `logging`, which refers to the process of recording events and errors that occur on a filesystem. Logging is essential for troubleshooting and debugging purposes, and can help to identify issues before they become major problems. Understanding how to configure and manage logging is essential for ensuring the reliability and performance of a GNU/Linux system. By mastering the concepts of checking GNU/Linux filesystem status, RHCSA candidates can demonstrate their expertise in managing and maintaining healthy and functional GNU/Linux systems.
Understanding GNU/Linux Journaling Filesystems
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of GNU/Linux journaling filesystems. Journaling filesystems are a type of filesystem that uses a journal to keep track of changes made to the filesystem, allowing for faster recovery in the event of a crash or power failure. The journal is a separate area of the disk that stores a record of all changes made to the filesystem, including file creations, deletions, and modifications.
RHCSA candidates should be familiar with the different types of journaling filesystems available in GNU/Linux, including `ext3`, `ext4`, `XFS`, and `JFS`. Each of these filesystems has its own strengths and weaknesses, and understanding their characteristics is essential for making informed decisions about which filesystem to use in a given situation. For example, `ext3` and `ext4` are widely used journaling filesystems that offer a good balance between performance and reliability, while `XFS` is a high-performance journaling filesystem that is well-suited for large storage systems.
In addition to understanding the different types of journaling filesystems, RHCSA candidates should also be familiar with the concept of `journaling modes`. Journaling modes refer to the way in which the journal is used to record changes to the filesystem. There are three main journaling modes: `data=journal`, `data=ordered`, and `data=writeback`. The `data=journal` mode is the most secure, as it records all data changes to the journal before writing them to the main filesystem. The `data=ordered` mode is a compromise between security and performance, as it records metadata changes to the journal, but not data changes. The `data=writeback` mode is the fastest, but also the least secure, as it does not record any changes to the journal.
RHCSA candidates should also be familiar with the concept of `journal size`, which refers to the amount of space allocated to the journal on the disk. The journal size can have a significant impact on the performance of the filesystem, as a larger journal can provide better performance, but also takes up more space on the disk. Understanding how to configure the journal size is essential for optimizing the performance of a journaling filesystem.
In terms of benefits, journaling filesystems offer several advantages over non-journaling filesystems, including `faster recovery` in the event of a crash or power failure, `improved data integrity`, and `better performance` in certain situations. Journaling filesystems can also provide `snapshot` capabilities, which allow for the creation of a temporary copy of the filesystem at a given point in time.
RHCSA candidates should also be familiar with the concept of `journal recovery`, which refers to the process of recovering a journaling filesystem after a crash or power failure. Journal recovery involves replaying the journal to restore the filesystem to a consistent state. Understanding how to perform journal recovery is essential for ensuring the reliability and integrity of a journaling filesystem.
Finally, RHCSA candidates should be familiar with the concept of `tuning` a journaling filesystem, which refers to the process of adjusting the configuration of the filesystem to optimize its performance. Tuning a journaling filesystem can involve adjusting the journal size, the journaling mode, and other parameters to achieve the best possible performance. Understanding how to tune a journaling filesystem is essential for optimizing the performance of a GNU/Linux system. By mastering the concepts of GNU/Linux journaling filesystems, RHCSA candidates can demonstrate their expertise in managing and maintaining reliable and high-performance GNU/Linux systems.
GNU/Linux Filesystem Topics: RAID and LVM
As a Red Hat Certified System Administrator, it is essential to have a solid understanding of advanced GNU/Linux filesystem topics, including RAID and LVM. RAID (Redundant Array of Independent Disks) is a technology that allows multiple disks to be combined into a single logical disk, providing improved performance, reliability, and fault tolerance. LVM (Logical Volume Manager) is a disk management system that allows administrators to manage disk space in a flexible and efficient way.
RHCSA candidates should be familiar with the different types of RAID configurations, including RAID 0, RAID 1, RAID 5, and RAID 6. Each of these configurations has its own strengths and weaknesses, and understanding their characteristics is essential for making informed decisions about which configuration to use in a given situation. For example, RAID 0 is a high-performance configuration that stripes data across multiple disks, but provides no redundancy or fault tolerance. RAID 1, on the other hand, is a mirrored configuration that provides excellent redundancy and fault tolerance, but requires twice the amount of disk space as the data being stored.
In addition to understanding the different types of RAID configurations, RHCSA candidates should also be familiar with the concept of `RAID levels`, which refer to the specific configuration of the RAID array. The most common RAID levels are RAID 0, RAID 1, RAID 5, and RAID 6. Understanding the characteristics of each RAID level is essential for designing and implementing a RAID configuration that meets the needs of a particular system or application.
RHCSA candidates should also be familiar with the concept of `LVM`, which is a disk management system that allows administrators to manage disk space in a flexible and efficient way. LVM provides a number of benefits, including the ability to create logical volumes that are larger than the physical disks, the ability to resize logical volumes dynamically, and the ability to move logical volumes between physical disks. Understanding how to use LVM is essential for managing disk space in a GNU/Linux system.
In terms of LVM components, RHCSA candidates should be familiar with the concept of `physical volumes` (PVs), `volume groups` (VGs), and `logical volumes` (LVs). Physical volumes are the individual disks that make up the LVM configuration, while volume groups are the collections of physical volumes that are used to create logical volumes. Logical volumes are the virtual disks that are created from the volume groups, and are the final storage devices that are used by the system or application.
RHCSA candidates should also be familiar with the concept of `LVM operations`, which include creating, resizing, and removing logical volumes, as well as adding and removing physical volumes from a volume group. Understanding how to perform these operations is essential for managing disk space in a GNU/Linux system.
In terms of benefits, RAID and LVM provide a number of advantages, including `improved performance`, `increased reliability`, and `flexible disk management`. RAID provides improved performance by striping data across multiple disks, and increased reliability by providing redundancy and fault tolerance. LVM provides flexible disk management by allowing administrators to create logical volumes that are larger than the physical disks, and to resize logical volumes dynamically.
Finally, RHCSA candidates should be familiar with the concept of `troubleshooting` RAID and LVM configurations, which involves identifying and resolving problems with the configuration. This can include issues such as disk failures, configuration errors, and performance problems. Understanding how to troubleshoot RAID and LVM configurations is essential for ensuring the reliability and performance of a GNU/Linux system. By mastering the concepts of RAID and LVM, RHCSA candidates can demonstrate their expertise in managing and maintaining high-performance and reliable GNU/Linux systems.
Conclusions
This concludes Article 6 of my RHCSA series. We discussed many aspects of controlling filesystems on GNU/Linux computer systems:
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of the fundamentals of GNU/Linux filesystems.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of mounting and unmounting GNU/Linux filesystems.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of GNU/Linux disk partitioning.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of optimizing GNU/Linux filesystem performance.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of GNU/Linux filesystem tunable parameters.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of checking GNU/Linux filesystem status.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of GNU/Linux journaling filesystems.
- As a Red Hat Certified System Administrator, it is essential to have a solid understanding of advanced GNU/Linux filesystem topics, including RAID and LVM.
References:
[1] 2020 - Lecture - CSCI 275: Linux Systems Administration and Security - Moe Hassan - CUNY John Jay College - NYC Tech-in-Residence Corps. Retrieved June 26, 2025 from https://academicworks.cuny.edu/cgi/viewcontent.cgi?article=1053&context=jj_oers