System requirements reference

This section provides information and guidelines for hardware, installation target, system, memory, and RAID when installing CentOS.

Hardware compatibility

To verify that your hardware is supported, see the Red Hat Hardware Compatibility List, available at https://access.redhat.com/ecosystem/search/#/category/Server.
To view supported memory sizes or CPU counts, see https://access.redhat.com/articles/rhel-limits for information.

Supported installation targets

An installation target is a storage device that stores CentOS and boots the system. CentOS supports the following installation targets for AMD64, Intel 64, and 64-bit ARM systems:

Storage connected by a standard internal interface, such as SCSI, SATA, or SAS
BIOS/firmware RAID devices
NVDIMM devices in sector mode on the Intel64 and AMD64 architectures, supported by the nd_pmem driver.
Fibre Channel Host Bus Adapters and multipath devices. Some can require vendor-provided drivers.
Xen block devices on Intel processors in Xen virtual machines.
VirtIO block devices on Intel processors in KVM virtual machines.

Red Hat does not support installation to USB drives or SD memory cards. For information about support for third-party virtualization technologies, see the Red Hat Hardware Compatibility List.

System specifications

The CentOS installation program automatically detects and installs your system’s hardware, so you should not have to supply any specific system information. However, for certain CentOS installation scenarios, it is recommended that you record system specifications for future reference. These scenarios include:

Installing CentOS with a customized partition layout

Record: The model numbers, sizes, types, and interfaces of the hard drives attached to the system. For example, Seagate ST3320613AS 320 GB on SATA0, Western Digital WD7500AAKS 750 GB on SATA1.

Installing CentOS as an additional operating system on an existing system

Record: Partitions used on the system. This information can include file system types, device node names, file system labels, and sizes, and allows you to identify specific partitions during the partitioning process. If one of the operating systems is a Unix operating system, CentOS may report the device names differently. Additional information can be found by executing the equivalent of the mount command and the blkid command, and in the /etc/fstab file.

If multiple operating systems are installed, the CentOS installation program attempts to automatically detect them, and to configure boot loader to boot them. You can manually configure additional operating systems if they are not detected automatically. See Configuring boot loader in Configuring software options for more information.

Installing CentOS from an image on a local hard drive

Record: The hard drive and directory that holds the image.

Installing CentOS from a network location

If the network has to be configured manually, that is, DHCP is not used.

Record:

IP address
Netmask
Gateway IP address
Server IP addresses, if required

Contact your network administrator if you need assistance with networking requirements.

Installing CentOS on an iSCSI target

Record: The location of the iSCSI target. Depending on your network, you may need a CHAP user name and password, and a reverse CHAP user name and password.

Installing CentOS if the system is part of a domain

Verify that the domain name is supplied by the DHCP server. If it is not, enter the domain name during installation.

Disk and memory requirements

If several operating systems are installed, it is important that you verify that the allocated disk space is separate from the disk space required by CentOS.

For AMD64, Intel 64, and 64-bit ARM, at least two partitions (/ and swap) must be dedicated to CentOS.
For IBM Power Systems servers, at least three partitions (/, swap, and a PReP boot partition) must be dedicated to CentOS.

You must have a minimum of 10 GiB of available disk space. See Recommended partitioning scheme for more information.

To install CentOS, you must have a minimum of 10 GiB of space in either unpartitioned disk space or in partitions that can be deleted. See Recommended partitioning scheme for more information.

Table 1. Minimum RAM requirements
Installation type	Recommended minimum RAM
Local media installation (USB, DVD)	768 MiB
NFS network installation	768 MiB
HTTP, HTTPS or FTP network installation	1.5 GiB

It is possible to complete the installation with less memory than the recommended minimum requirements. The exact requirements depend on your environment and installation path. It is recommended that you test various configurations to determine the minimum required RAM for your environment. Installing CentOS using a Kickstart file has the same recommended minimum RAM requirements as a standard installation. However, additional RAM may be required if your Kickstart file includes commands that require additional memory, or write data to the RAM disk. See the Performing an advanced installation document for more information.

RAID requirements

It is important to understand how storage technologies are configured and how support for them may have changed between major versions of CentOS.

Hardware RAID

Any RAID functions provided by the mainboard of your computer, or attached controller cards, need to be configured before you begin the installation process. Each active RAID array appears as one drive within CentOS.

Software RAID

On systems with more than one hard drive, you can use the CentOS installation program to operate several of the drives as a Linux software RAID array. With a software RAID array, RAID functions are controlled by the operating system rather than the dedicated hardware.

When a pre-existing RAID array’s member devices are all unpartitioned disks/drives, the installation program treats the array as a disk and there is no method to remove the array.

USB Disks

You can connect and configure external USB storage after installation. Most devices are recognized by the kernel, but some devices may not be recognized. If it is not a requirement to configure these disks during installation, disconnect them to avoid potential problems.

NVDIMM devices

To use a Non-Volatile Dual In-line Memory Module (NVDIMM) device as storage, the following conditions must be satisfied:

Version of CentOS is 7.6 or later.
The architecture of the system is Intel 64 or AMD64.
The device is configured to sector mode. Anaconda can reconfigure NVDIMM devices to this mode.
The device must be supported by the nd_pmem driver.

Booting from an NVDIMM device is possible under the following additional conditions:

The system uses UEFI.
The device must be supported by firmware available on the system, or by a UEFI driver. The UEFI driver may be loaded from an option ROM of the device itself.
The device must be made available under a namespace.

To take advantage of the high performance of NVDIMM devices during booting, place the /boot and /boot/efi directories on the device.

The Execute-in-place (XIP) feature of NVDIMM devices is not supported during booting and the kernel is loaded into conventional memory.

Considerations for Intel BIOS RAID Sets

CentOS uses mdraid for installing on Intel BIOS RAID sets. These sets are automatically detected during the boot process and their device node paths can change across several booting processes. For this reason, local modifications to the /etc/fstab, /etc/crypttab or other configuration files that refer to the devices by their device node paths may not work in CentOS. It is recommended that you replace device node paths (such as /dev/sda) with file system labels or device UUIDs. You can find the file system labels and device UUIDs using the blkid command.