Chapter 9. File Systems

The Ceph File System (CephFS) kernel module enables Red Hat Enterprise Linux nodes to mount Ceph File Systems from Red Hat Ceph Storage clusters. The kernel client in Red Hat Enterprise Linux is a more efficient alternative to the Filesystem in Userspace (FUSE) client included with Red Hat Ceph Storage. Note that the kernel client currently lacks support for CephFS quotas.

The CephFS kernel client was introduced in Red Hat Enterprise Linux 7.3 as a Technology Preview, and since the release of Red Hat Ceph Storage 3, CephFS is fully supported.

For more information, see the Ceph File System Guide for Red Hat Ceph Storage 3: https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/3/html/ceph_file_system_guide/. (BZ#1205497)

You can now modify the label attribute of mounted XFS file systems using the xfs_io utility:

# xfs_io -c "label -s new-label" /mount-point

Previously, it was only possible to modify labels on unmounted file systems using the xfs_admin utility, which is still supported. (BZ#1322930)

Client and server support for parallel NFS (pNFS) SCSI layouts is now fully supported. It was first introduced in Red Hat Enterprise Linux 7.3 as a Technology Preview.

Building on the work of block layouts, the pNFS layout is defined across SCSI devices and contains sequential series of fixed-size blocks as logical units that must be capable of supporting SCSI persistent reservations. The Logical Unit (LU) devices are identified by their SCSI device identification, and fencing is handled through the assignment of reservations. (BZ#1305092)

The ima-evm-utils package is now fully supported when used on the AMD64 and Intel 64 architecture. Note that on other architectures, ima-evm-utils remains in Technology Preview.

The ima-evm-utils package provides utilities to label the file system and verify the integrity of your system at run time using the Integrity Measurement Architecture (IMA) and Extended Verification Module (EVM) features. These utilities enable you to monitor if files have been accidentally or maliciously altered. (BZ#1627278)