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Red Hat Enterprise Linux 6 allows for better management of power consumption, taking and advantage of greater processing and memory resources, and better withstanding of hardware failures. Scalability is increased which helps meet the needs of larger systems. There is also an updated operating system kernel.

A summary of important improvements are listed below.

Kernel and Performance

  • Based on Linux 2.6.32 kernel
  • Tickless Kernel
  • Active State and Aggressive Link Power Management
  • LRU algorithm for memory management
  • Per-LUN flush daemons for improvement in enterprise applications.
  • Ticketed locks for fair acquisition for spinlocks in SMP systems.


  • Virtualization based on KVM hypervisor.
  • Completely Fair Queuing to assist KVM.
  • Paravirtualization capabilities.
  • Spinlock subsystem and VM channel.
  • More memory and CPU available per guest.

File System Capabilities

  • Ext4 file system: Successor to Ext3, provides improved check times. No limit on number of sub-directories within a directory. Uses delayed allocation for reduced fragmentation.
  • XFS file system: suited for handling large files with streaming I/O. Provides capability for native backup and restore utilities.
  • NFSv4 network file system: Improved tracking of file state between client and server, file delegation that allows cached files to be modified. Support of sophisticated security protocols.
  • GFS2 shared store file system: clustered filesystem that shares data with GFS2 nodes.


  • Svirt to provide containment and isolation of virtual guests.
  • Xace brings multi-level security to desktop environments.
  • Kiosk capabilities to allow read only environments to be created for public use.
  • Policykit provides authorization for user applications.
  • Sandboxing feature to containerize potentially insecure applications.


  • OpenChange support allows for MAPI access to Microsoft Exchange servers.
  • VDI/HVD capabilities for centralized hosting of Microsoft Windows and Red Hat Enterprise Linux desktops.
  • SPICE protocol for communication between server and client.


  • UDP-lite for multimedia protocols.
  • IPv6 mobility.
  • TCP-YeAH congestion control algorithms.
  • Multi-queue transmit and RCU algorithms.
  • Datacenter bridging support with 802/1p/802.1Qaz.
  • Updated NFS/CIFS/RDMA kernel subsystems.