Chapter 29. Kernel

RAID 4 and RAID 10 creation and activation fully supported

In Red Hat Enterprise Linux 7.3, existing RAID4 or RAID10 logical volumes created with previous releases failed to activate. Additionally, users were instructed not to create new RAID4 logical volumes created under Red Hat Enterprise Linux 7.3 as these might fail to activate with later releases and updates. With this update, Red Hat Enterprise Linux 7.4 fully supports RAID 4 and RAID 10 creation and activation and rejects invalid RAID 4 and RAID 10 layouts which may have been created with Red Hat Enterprise Linux 7.3. (BZ#1385149)

kdump now works with legacy type 12 NVDIMMs

Previously, systems with legacy type 12 Non-Volatile Dual In-line Memory Modules (NVDIMMs), either real dual in-line memory modules (DIMMs), or emulated using the memmap=XG!YG kernel command line parameter, were unable to successfully capture a kernel crash dump. For systems with real NVDIMMs, attempts to capture a kernel crash dump occasionally resulted in data corruption. With this update, the underlying source code has been fixed, and the systems with legacy type 12 NVDIMMs can now capture the kernel crash dump as expected. (BZ#1351098)

Creating a file that inherits ACLs no longer loses mask

Previously, creating a file that inherited Access Control Lists (ACLs) caused the mask to be lost, unlike on a local file system. With this update, clients using NFSv4.2 can set the umask attribute when creating files to cause the server to apply umask always except when inheriting permissions from the parent directory. As a result, new NFS files get the same permissions as files created locally. Note that you need to apply this update on both your NFS clients and NFS servers, and mount with the -overs=4.2 parameter. (BZ#1217546)