Chapter 1. Overview The Storage Administration Guide contains extensive information on supported file systems and data storage features in Red Hat Enterprise Linux 6. This book is intended as a quick reference for administrators managing single-node (that is, non-clustered) storage solutions. The Storage Administration Guide is split into two parts: File Systems, and Storage Administration. The File Systems part details the various file systems Red Hat Enterprise Linux 6 supports. It describes them and explains how best to utilize them. The Storage Administration part details the various tools and storage administration tasks Red Hat Enterprise Linux 6 supports. It describes them and explains how best to utilize them. 1.1. What's New in Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 6 features the following file system enhancements: File System Encryption (Technology Preview) It is now possible to encrypt a file system at mount using eCryptfs [1] , providing an encryption layer on top of an actual file system. This "pseudo-file system" allows per-file and file name encryption, which offers more granular encryption than encrypted block devices. For more information about file system encryption, refer to Chapter 3, Encrypted File System . File System Caching (Technology Preview) FS-Cache [1] allows the use of local storage for caching data from file systems served over the network (for example, through NFS). This helps minimize network traffic, although it does not guarantee faster access to data over the network. FS-Cache allows a file system on a server to interact directly with a client's local cache without creating an overmounted file system. For more information about FS-Cache, refer to Chapter 10, FS-Cache . Btrfs (Technology Preview) Btrfs [1] is a local file system that is now available. It aims to provide better performance and scalability, including integrated LVM operations. For more information on Btrfs, refer to Chapter 4, Btrfs . I/O Limit Processing The Linux I/O stack can now process I/O limit information for devices that provide it. This allows storage management tools to better optimize I/O for some devices. For more information on this, refer to Chapter 23, Storage I/O Alignment and Size . ext4 Support The ext4 file system is fully supported in this release. It is now the default file system of Red Hat Enterprise Linux 6, supporting an unlimited number of subdirectories. It also features more granular timestamping, extended attributes support, and quota journaling. For more information on ext4, refer to Chapter 6, The Ext4 File System . Network Block Storage Fibre-channel over Ethernet is now supported. This allows a fibre-channel interface to use 10-Gigabit Ethernet networks while preserving the fibre-channel protocol. For instructions on how to set this up, refer to Chapter 32, Configuring a Fibre-Channel Over Ethernet Interface . [1] This feature is being provided in this release as a technology preview . Technology Preview features are currently not supported under Red Hat Enterprise Linux subscription services, may not be functionally complete, and are generally not suitable for production use. However, these features are included as a customer convenience and to provide the feature with wider exposure. You are free to provide feedback and functionality suggestions for a technology preview feature before it becomes fully supported. Erratas will be provided for high-severity security issues.

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