Exkurs: Configuring a software RAID upon interactive installation
This Exkurs describes the configuration of a software RAID as part of an interactive Fedora Server Edition installation. In this case, the RAID capability is provided by operating system drivers and processed bei the computer CPU. It does not cover firmware raid (also called Windows RAID), which provide this capability via the computer internal firmware, nor hardware raid, where dedicated integrated hardware modules or adapters completely relieve the computer CPU of the raid processing.
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You are in the Fedora Server documentation staging area! These documents are not approved yet and may be incomplete and/or incorrect. Take everything here with a grain of salt! You would probably prefer to study the published documentation. Status of this document: Awaiting review (Jan 18, 2025). |
The RAID configuraton starts at the "Installation Destination" window.
The Local Standard Disk list must include at least two hard disks. And please, ignore the USB drive that provides the installation system, in case Anaconda doesn’t hide the installation media anyway.
Before you start with partitioning, you have to determine the boot type of your system, UEFI boot or BIOS (or legacy) boot system. Fedora defaults to the GPT partitioning scheme which was created with UEFI boot systems in mind. On a BIOS boot system, it requires a special partition.
| Just in case you need a DOS/MBR partitioning scheme for some good reason, you can override the GPT default by adding "inst.mbr" to the kernel boot parameter at the initial boot screen. |
If you don’t know the type of your system for sure, you can check the system now. Open a temporay shell by using <alt>+<ctrl>+<F2> and type into the terminal window:
# [ -d /sys/firmware/efi ] && echo UEFI || echo BIOSThe command shows in the next line either UEFI or BIOS. Use <alt>+<ctrl>+<F6> to return to the installation screen.
There are then two installation options:
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The "Custom" option
This way you just specify the mountpoints and Anaconda performs all the necessary steps for you. If needed you can adjust some properties afterwards. That’s the comfortable way.
Unfortunately, Anaconda does not necessarily keep the arrangement of the partitions that you have chosen, but sorts the partitions as it sees fit. This causes no problems at all in everyday operation. But if, for example, you have placed a partition at the end to preserve the possibility of making adjustments later, that could go wrong.
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the "Advanced Custom (Blivet-GUI)" option
This way, you can and must perform each individual step of partitioning, configuring LVM volumes and creating file systems by yourself. This is the more laborious way.
The advantage is that you can define every detail and you will get a partitioning exactly according to your plan. And the GUI supports the work very effectively.
Select all drives you want to include in the prospective RAID drive, click on the partitioning option you want to use and then on Done in the uper left corner.
Custom partitioning
Anaconda opens a new window:
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Check all disks for existing partitions
If the area beyond Unknown contains one or more partition, check whether you want to retain, reuse, or delete it. Mind that you can only reuse partitions that are set up identically on all disks.
To delete a partition, click on it and then on the '-' sign at the bottom. At the end, all disks must either be empty or identically partitioned.
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On a BIOS boot system only, create a biosboot partition on each disk
On a BIOS boot system, a GPT partition table as used by Fedora requires a small BIOSBoot partition for the Grub boot loader. Create it at the beginning of each disk to keep the system operational when one disk fails. Skip this step, if your host uses UEFI!
Use the "+" sign to add a partition. In the Mount Point field select 'biosboot' and set a size of 1 MiB.
A biosboot entry appears in the left New Fedora 41 Installation section on one of he disks.
Repeat it and you see a second entry, usually on the same disk.
The BiosBoot installation
Select the new entry and click on Modify at Device(s). In the device list select one of the other disks. Then select Update Settings.
Anaconda updates the list of partitions in the New Fedora 41 installation section so that the biosboot partition is now the first partition on different disks.
The adjusted BiosBoot installation
Repeat the step until all disks have a biosboot partition. This is necessary so that the system can boot from any of the other disks if the first disk fails.
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On a UEFI boot system only, create an EFI partition
Use the "+" sign to add a partition. The "Add a new Mount Point form" form opens up
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select /boot/efi as the mount point
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enter 600 Mib as size
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Tick "Add Mount Point"
The installation window refreshes and now shows a /boot/efi partition on the left side under SYSTEM and a number of properties for this partition on the right side.
Initial EFI system partition
Anaconda sets up an EFI partition on the first disk. But a RAID system must be able to boot from any of the available disks, not just the first one. Otherwise, the system would be paralyzed if that failed. One solution is to set up the EFI partition as a RAID as well.
Find the property Device Type and use the drop down list to change Standard partition to RAID. In the right side shows up a new selection box RAID level showing initially RAID1 (mirroring) in this example, because we have just 2 disks. Leave the file system as “EFI System Partition”. Choose an optional label, e.g. sysefi, and And trigger “Update Settings” further below.
Final EFI system partition properties
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Add a boot Partition
Tick the "+" sign and a form "Add a new Mount Point" opens again.
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select /boot as the mount point
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enter 1 Gib as size
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Tick "Add Mount Point"
A new mount point is created on sda1. On the right side there is a form to show and modify some properties. Find the property Device Type and use the drop down list to change Standard partition to RAID. In the right side shows up a new selection box RAID level showing initially RAID1 (mirroring) in this example, because we have just 2 disks. Choose the RAID level you wish and then click on Update Settings further down.
Anaconda updates the form and the list beyond New Fedora 41 Installation. The sdx partition is gone and replaced by a (device) name, the same one you find in the property form on the right side. In the form you can add a label, e.g. sysboot, if you like, and Update Settings again.
Final properties of the boot device (raid partition)
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Add a root mount point
Use the "+" sign to add another Moint Point
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select / as the mount point
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enter 15 Gib as size
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Tick "Add Mount Point"
Anaconda creates a new mount point. From the context Anaconda guesses to assign the device type LVM, to create a Volume Group using the default name fedora appending the systems hostname, if you already configured the network, and to assign the device name root. The size of 15 GiB is the same as a default configuration would do. That’s a lot of work that Anaconda saves you.
Anaconda generated LVM root volume and filesystem
Now you have the opportunity the adjust Anacondas guessings.
The most important one is to adjust the RAID level. Anaconda configures a LVM without RAID by default. Tick the modify button of the LVM property.
Anaconda LVM properties form
Select a proper RAID level and check the size policy.
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Automatic means that the size of the partition and the Volume Group is just as large as the Logical Volumes you create with Anaconda here. That provides you a maximum of flexibilty to later adjust the storage organisation but also involves some additional steps to handle the Volume Group and its partition when you want do add a Logical Volume and file system.
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Maximum size expands the Volume Group to fill up the complete hard disk, so you can add Logical Volumes with a minimum of effort. That is the recommended way for medium size disks.
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Fixed size lets you specify a size that fulfills your foreseeable requirements and leaving some space for later adjustments that come up as a surprise.
This option also allows for an even stronger separation of system and user data. Specify a fixed size of 20-30 GiB for a system volume group (named e.g. fedora_sysvg). This contains the root file system and, if applicable, further system-related logical volumes. In the remaining space you will later set up a user volume group (correspondingly named fedora_usrvg) and logical volumes for user data. This gives you the greatest possible flexibility to adapt the system area to changes in demand or technical developments without touching the precious user data at all. This is recommended for large hard disks, servers with a planned longtime lifespan, or remotely located servers.
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Customize the storage organisation to your requirements
Finally, you can further customize the storage organization to your requirements.
Some adminmistrators like to confine the /var/log subdirectory in its own Logical Volume. This prevents excessive logging from filling up the root file system. But also vice versa, that excessive outputs of a program fill up the root file system to such an extent that no more log outputs can be saved and troubleshooting is made more difficult.
Finally, click on Done, in the upcomming list accept the Changes and return now to the original guide, probably Fedora Server interactive local installation guide.
Advanced Custom partitioning
Anaconda opens a new window:
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Check all disks for existing partitions
If there are partitions on any of the hard disks, delete the partitions if they are no longer needed. Note that you can only reuse partitions that are set up identically on all hard disks.
To delete a partition, click on it and then on the “-” sign below. In the end, all hard disks must either be empty or identically partitioned. In the following, we assume that the hard disks are empty.
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On a BIOS boot system only, create a biosboot partition on each disk
On a BIOS boot system, a GPT partition table as used by Fedora requires a small BIOSBoot partition for the Grub boot loader. Create it at the beginning of each disk to keep the system operational when one disk fails. Skip this step, if your host uses UEFI!
Usually, the first Disk is sda and already selected. A large blue bar at the top represents the disk. Otherwise, click onto the left side onto the sda symbol. With the "plus" symbol just beyond the central sda area you start to create a partition.
Create a BIOS Boot partition
First select "Bios Boot" in the „Filesystem“ selection field and then enter 1 MiB as the size. An OK creates the partition and updates the free space area. 1 MiB is quite sufficient, but sometimes the dialogue insists on 2 MiB and corrects the entry accordingly. That’s fine, too.
Next, click on sdb and thus activate it for editing. Repeat the process to create a BIOSBoot partition as before.
When both BIOSBoot partitions have been created, check again whether the size and position are actually the same in both cases! You can switch between the two disk views by clicking on the sda1 and sda2 icons respectively.
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On a UEFI boot system only, create an EFI partition
If you have not already done so, activate the first hard disk, usually sda, by clicking on the icon in the left column. With the "plus" symbol just beyond the central sda area you start to create a partition.
Creating EFI system partition
Anaconda sets up an EFI partition on the first disk. But a RAID system must be able to boot from any of the available disks, not just the first one. Otherwise, the system would be paralyzed if that failed. One solution is to set up the EFI partition as a RAID as well. Therefore, select "Software RAID" in the "Device type" selection box and replace "partition". Then fill out the rest of the form as indicated.
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select sda and sdb as RAID members
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select RAID level raid1
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enter 0.6 GiB size
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select Filesystem "EFI System Partition"
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enter Label "sysefi"
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enter Name "boot_efi"
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Enter Mountpoint /boot/efi
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Tick "OK"
The installation window refreshes and now shows a new RAID entry in the left column and a boot_efi partition in the sda disk.
Partitions list including EFI system partition
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Creating a boot Partition
Click into the free space on sda to activate it and tick the "+" sign again to open a new device form.
Creating a boot partition
In the “Device type” selection box, select “Software RAID” . The form changes. Then fill out the rest of the form as indicated.
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select sda and sdb as RAID members
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select RAID level raid1
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enter 1.0 GiB size
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keep Filesystem "xfs"
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enter Label "sysboot"
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enter Name "boot"
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Enter Mountpoint /boot
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Tick "OK"
The installation window refreshes and now shows another new RAID entry in the left column and a boot partition in the sda disk.
Partitions list including EFI and boot partitions
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Creating a system Volume Group
Click into the free space on sda to activate it and tick the "+" sign again to open a new device form.
Creating a system Volme Group partition
Again, in the “Device type” selection box, select “Software RAID” and then fill out the rest of the form as indicated.
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select sda and sdb as RAID members
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select RAID level raid1
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Specify the size of the partition. There are basically three options.
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Leave the size as suggested by the form, which fills the rest of the hard disk. Both system and user data are stored in a common volume group. This is appropriate for hosts with a planned lifespan of a few years or less and/or a disk capacity of less than 0.5 - 1 TB.
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Set aside a 20–30/50 GiB partition for the system area and, in the next step, another partition exclusively for user data. This is particulary recommended for systems with a planned longtime lifespan, a hard disk capacity of more than 1–2 TiB, and especially for systems in remote data centers where there is never any possibility of accessing the system console. In the latter case, it is especially important to keep system and user areas strictly separated as far as possible on the same hard disk, in order to be able to carry out any system work without ever having to touch the precious user data.
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In either case, leave some free space at the end to allow for possible future adjustments to changing and unpredictable needs.
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In this example, we use a 30 GiB system area and the entire rest for a dedicated user area.
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Select "physical volume (LVM)" for Filesystem.
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enter Name "syspv"
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Tick "OK"
The list view refreshes and shows the harddisks with the 3 partitions and on the left column an additional RAID device.
Partitions list including EFI, boot and physical volume partitions
In contrast to other GUIs, a volume group (VG) is not created immediately, but a "physical volume" is created first. Many other GUIs perform this step implicitly and automatically.Double-click onto the syspv icon in the left bar to activate it and then on the Plus sign to open a device creation form.
Partitions list including EFI, boot and physical volume partitions
Leave the Device type and Size field as is und enter "sysvg" into the Name field. Tick OK to submit the form.
The overview list screen now shows a new Volume Group device "sysvg" beyond a new category "LVM".
Devices list showing partitions, volume groups and RAID devices
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Optional: Creating a user Volume Group
If you have opted for a separate user area as recommended, you should now create a corresponding volume group. Repeat the steps from the previous section accordingly.
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Double-click on sda and into the free space to activate it and tick the "+" sign again to create an additional RAID partition and physical volume.
Creating a user physical volume on RAID
Either leave the suggested size value as it is to set up the entire free area for user data, or choose a smaller value to keep free disposition storage.
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Double-click onto the usrpv icon in the left bar to activate it and then on the Plus sign to open a device creation form.
Partitions list including EFI, boot and physical volume partitions
Leave the Device type and Size field as is und enter "usrvg" into the Name field. Tick OK to submit the form.
The overview list screen now shows a new Volume Group device "sysvg" beyond a new category "LVM".
Devices list showing partitions, two volume groups and RAID devices
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Creating the ROOT file system
As in the previous steps, clicking on symbol sysvg activates the unit for editing and clicking on the free area releases the plus sign. A click on the plus sign opens the dialogue for setting up a file system.
Creating the ROOT file system
Leave the Device type and Avalable devices as is.
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Specify the size of the root file system. A value of 12 GiB for the mere system files is large enough for the usual use cases and still has a lot of leeway for unusual situations.
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Complete the other fields as indicated and tick OK.
Devices list showing partitions, two volume groups and RAID devices
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Some typical optional adjustments to the storage organization
Finally, you can further customize the storage organization to your requirements.
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Optional: Create a separate log file system
Some adminmistrators like to confine the /var/log subdirectory in its own Logical Volume. This prevents excessive logging from filling up the root file system. But also vice versa, that excessive outputs of a program fill up the root file system to such an extent that no more log outputs can be saved and troubleshooting is made more difficult.
As in the previous steps, clicking on symbol sysvg activates the unit for editing and clicking on the free area releases the plus sign. A click on the plus sign opens the dialogue for setting up a file system.
Creating log file system
Leave the Device type and Avalable devices as is
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Specify the size of the file system. A value of 3 or 5 GiB is usually large enough.
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Complete the form as indicated
Devices list showing the /var/log file system
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Optional: Setting up a home directory storage space
An Internet server that only provides web and e-mail services usually only allows administrative users that do not use the server to store important personal data. A separate file system is often superfluous.
But sometimes they need to upload some data for further processing on the server. You may want to keep those separate from the system files and create a small home file system, maybe just in the system Volume Group if you decided for a strict separation as recommended above.
For a large number of users, use the user area, if available
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Select a siutable Volume Group, double-click on the device in the left column (sysvg or usrvg), and then into the free space to release the "plus" button.
Creating a home file system
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Leave the Device type and Avalable devices as is
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Specify a reasonable size of the home file system. For a system with only administravie users, a value of 3 or 5 GiB is usually large enough.
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Complete the form as indicated
Storage overview including a home file system
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Optional: Setting up a server (/srv) storage space
According to the Filesystem Hierarchy Standard (FHS), a system should store site-specific data served by the server, such as data and scripts for web servers, data offered by FTP servers, etc. in /srv. These belong into a separate file system.
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Select a suitable Volume Group, in this example usrvg if available. Double-click on the device in the left column and then into the free space to release the "plus" button.
Creating a srv file system
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Leave the Device type and Avalable devices as is.
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Specify a reasonable size depending on your system plannings.
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Complete the form as indicated.
Devices list showing the srv file system
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If applicable: Setting up a virtual machine’s storage space
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Select a suitable Volume Group, in this example usrvg if available. Double-click on the device in the left column and then into the free space to release the "plus" button.
Creating a libvirt file system
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Leave the Device type and Avalable devices as is.
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Specify a reasonable size depending on your system plannings.
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Complete the form as indicated.
Devices list showing libvirt file system
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Finally, click on Done, in the upcomming list accept the Changes and return now to the original guide, probably Fedora Server interactive local installation guide.
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