New Features and Changes

System Requirements and Limits

You can install Oracle Linux 7 on x86-64 systems with up to 2048 logical CPUs and 64 TB of memory. The theoretical upper limit is 5120 logical CPUs and 64 TB of memory, but Oracle has not tested this configuration. A minimum of 2 logical CPUs and 1 GB of memory per logical CPU is recommended. Although the minimum disk space required for installation is 1GB, a minimum of 5 GB is recommended.

File System, Storage, and Address Space Limitations

The following table lists the maximum file size and maximum file system size for the btrfs, ext4, and XFS file systems.

File System Type	Maximum File Size	Maximum File System Size
btrfs	50 TB	50 TB
ext4	50 TB	50 TB
XFS	16 TB	500 TB

The maximum supported size for a bootable LUN is 50 TB. GPT and UEFI support are required for LUNs larger than 2 TB.

The maximum size of the address space that is available to each process is 128 TB.

Shipped Kernels

Oracle Linux 7 Update 3 ships with the following kernel packages:

kernel-3.10.0-514.el7: Red Hat Compatible Kernel (RHCK).
kernel-uek-4.1.12-61.1.18.el7uek: Unbreakable Enterprise Kernel Release 4 update 2 (UEK R4u2), which is the default kernel.

Oracle Linux 7 Update 3 continues to support, but does not ship with, the latest Unbreakable Enterprise Kernel Release 3 updates. At the time of publication this is UEK R3u7.

The kernel source code for the shipped kernel is available after the initial release via a public git source code repository at https://oss.oracle.com/git/?p=linux-uek.git.

Support Tools

Oracle Linux 7 includes tools to assist with the resolution of runtime issues. This section describes new features and changes to these tools in this update.

Kdump Configuration During Installation

It is now possible to configure Kdump during non-graphical installation. For limitations on using the crashkernel=auto setting, see Crash Kernel auto Setting.

makedumpfile Support for Large Memory Images

makedumpfile can now use sadump format for dumps of more than 16 TB of physical memory.

Kpatch removed

The upstream Kpatch RPM has been removed from Oracle Linux. Customers who wish to patch their running kernel with zero downtime should evaluate Oracle's Ksplice technology, which is included at no additional cost with Oracle Linux Premier support.

Load Balancing and High Availability

Oracle Linux 7 includes the Keepalived and HAProxy technologies for balancing access to network services while maintaining continuous access to those services.

Keepalived uses the IP Virtual Server (IPVS) kernel module to provide transport layer (Layer 4) load balancing, redirecting requests for network-based services to individual members of a server cluster. IPVS monitors the status of each server and uses the Virtual Router Redundancy Protocol (VRRP) to implement high availability.

HAProxy is an application layer (Layer 7) load balancing and high availability solution that you can use to implement a reverse proxy for HTTP and TCP-based Internet services.

For more information, see Oracle Linux 7: Administrator's Guide.

MySQL Community and MariaDB Packages

Note that the MySQL Community packages in this release update have been updated from MySQL Community 5.6 to MySQL Community 5.7.

In the initial release of Oracle Linux 7, the MySQL Community 5.6 packages were provided on the Oracle Linux 7 full installation DVD image but were not installable using the Anaconda installer or kickstart. The ISO image for this update to Oracle Linux 7 provides support for installing either MySQL 5.7 or MariaDB by using either the Anaconda installer or kickstart.

It is not possible to install MySQL and MariaDB on the same system as package conflicts exist. Installing the MySQL packages replaces any conflicting MariaDB packages.

By default, neither MySQL 5.7 packages nor MariaDB packages are installed. It is possible to install either the MySQL 5.7 package group or the MariaDB package group on a system by using the graphical installer or kickstart, but not both package groups.

To install the MySQL 5.7 packages using kickstart, specify the @mysql package group in the %packages section. If you also specify @mariadb, it is ignored.

To install the MariaDB packages using kickstart, specify @mariadb but not @mysql in the %packages section.

Note:

If you want to install MariaDB, you must deselect the MySQL repository. Otherwise, MySQL is installed even if you select only the MariaDB group. (Bug ID 22238684)

The MySQL Community 5.7, MySQL Community 5.6 and MySQL Community 5.5 packages are also available on the Unbreakable Linux Network (ULN) and Oracle Linux yum server.

(Bug ID 20069488)

Spacewalk Client Registration

It is not necessary to install the Spacewalk client before registering an Oracle Linux 7 Update 3 system with a Spacewalk server. Instead, you can use the rhnreg_ks command, specifying the CA certificate file for the server, the server URL, and the activation key to be associated with the system.

To register a system as a client of a Spacewalk server:

Download the CA certificate file RHN-ORG-TRUSTED-SSL-CERT to the system.

In a browser tab, navigate to http://swksvr_FQDN/pub, where swksvr_FQDN is the fully qualified domain name of the Spacewalk server, and download the CA certificate file RHN-ORG-TRUSTED-SSL-CERT to /usr/share/rhn/.

Alternatively, you can use wget from the command line, for example:
```
wget -q -O /usr/share/rhn/RHN-ORG-TRUSTED-SSL-CERT http://swksvr_FQDN/pub/RHN-ORG-TRUSTED-SSL-CERT
```
Register the system with Spacewalk using the rhnreg_ks command, using the --sslCACert option to specify the certificate.
```
sudo rhnreg_ks --sslCACert=/usr/share/rhn/RHN-ORG-TRUSTED-SSL-CERT --serverUrl=https://swksvr_FQDN/XMLRPC --activationkey=activation_key
```
Specify the Spacewalk server or proxy by its fully qualified domain name.

If you need to re-register a Spacewalk client with a Spacewalk server, additionally specify the --force option.

Oracle recommends installing the Spacewalk client software after registration to support all of the features provided by Spacewalk, which include provisioning and auditing.

To install the Spacewalk client software after registration, subscribe the server to a Spacewalk Client 2.2 software channel and use yum to install the packages:

sudo yum install rhn-client-tools rhn-check rhn-setup rhnsd m2crypto yum-rhn-plugin

(Bug ID 20656368)

UEFI Secure Boot Support

This update allows you to install and use Oracle Linux 7 on systems that have enabled UEFI Secure Boot. A system in Secure Boot mode will load only boot loaders and kernels that have been signed by Oracle. Oracle has updated the kernel and grub2 packages to sign them with a valid Extended Validation (EV) certificate. The EV certificate has been compiled into the shim binary and has been signed by Microsoft. This feature is fully supported on Oracle Linux 7 update 3.

If you have previously enabled Secure Boot while it was available under technology preview, you must ensure that the shim, grub2 and kernel packages are updated as an atomic operation if you intend to upgrade the system. If these packages are not all updated, the Secure Boot process may break and must be disabled until a full system upgrade is complete.

Technology Preview

Features that are currently under technology preview when using UEK R4u2 are described in the release notes at Unbreakable Enterprise Kernel documentation

Features that are currently under technology preview when using UEK R3QU7 are described in the release notes at Unbreakable Enterprise Kernel documentation

For the RHCK, the following features are currently under technology preview:

Systemd:
- Importd features for container image imports and exports
File Systems:
- DAX (Direct Access) for direct persistent memory mapping from an application. This is under technical preview for the ext4 and XFS file systems.
- Block and object storage layouts for parallel NFS (pNFS).
- SCSI layout for parallel NFS (pNFS), including support for both client and server configurations.
- OverlayFS remains in technical preview.
- btrfs file system. Oracle supports btrfs with UEK R3 and UEK R4.
Kernel:
- Heterogeneous memory management (HMM).
- Usernamespace (security features for isolating Linux containers from the host).
- 10GbE RoCE Express for RDMA.
- ocrdma and libocrdma packages for RDMA over RoCE.
- No-IOMMU mode virtual I/O feature.
Networking
- Support for a Cisco proprietary User Space Network Interface Controller in UCM servers provided in the libusnic_verbs driver
- Cisco VIC InfiniBand kernel driver that provides similar functionality to RDMA on proprietary Cisco architectures.
- Trusted Network Connect.
- Single-Root I/O virtualization (SR-IOV) in the qlcnic driver.
- nftables and libnftnl network filtering and classification functionality
Storage
- LVM2 support for RAID-level takeover (striped RAID4, linear RAID1 and mirror RAID1)
- Multi-queue I/O scheduling for SCSI (scsi-mq). This functionality is disabled by default.
- The plug-in for the libStorageMgmt API used for storage array management. The libStorageMgmt API is now fully supported, but the plugin is under technology preview.
- DIF/DIX for data integrity checking on SCSI devices other than certain, specified native HBA and storage hardware. Oracle supports DIF/DIX with UEK R3 and UEK R4.

Compatibility

Oracle Linux maintains user-space compatibility with Red Hat Enterprise Linux, which is independent of the kernel version that underlies the operating system. Existing applications in user space will continue to run unmodified on the Unbreakable Enterprise Kernel Release 4 (UEK R4) and no re-certifications are needed for RHEL certified applications.

To minimize impact on interoperability during releases, the Oracle Linux team works closely with third-party vendors whose hardware and software have dependencies on kernel modules. The kernel ABI for UEK R4 will remain unchanged in all subsequent updates to the initial release. UEK R4 contains changes to the kernel ABI relative to UEK R3 that require recompilation of third-party kernel modules on the system. Before installing UEK R4, verify its support status with your application vendor.