At Last, Red Hat Enterprise Linux 6 - page 2
Bye Xen, Hello KVM
Among the new Linux kernel features in RHEL 6 is a technology called "control groups," which is a means of controlling resources on the system where users can define how much memory, I/O and CPU utilization any process is allowed to accumulate.
Additionally, Burke noted that there is better power management in RHEL 6 with a Linux kernel feature called the "tickless kernel," which avoids the need to interrupt the system to keep time.
Asynchronous I/O for virtualization also makes its debut in RHEL 6. Burke explained that the feature makes it possible for, say, database workloads to be able to have higher volumes of concurrent I/O operations.
RHEL 6 will also include the next-generation Ext4 Linux filesystem by default. In contrast, RHEL 5 shipped with the older Ext3 system. Ext4 entered the mainline Linux kernel in December 2008.
"Ext4 has scalability enhancements and it can scale up to 16-terabyte filesystems," Burke said. "But another advantage of Ext4 is the consistency check that can be an order of magnitude faster on Ext4 than it was on Ext 3."
For example, Burke noted that in cases where users had 8TB filesystems, it could have taken hours for repair time on a consistency check with Ext3. With Ext4, that same check could be done in minutes.
While Ext4 is being included by default, the Btrfs next-generation Linux filesystem is being included as an optional technology preview. Along with Oracle, Red Hat is one of the leading contributors to the Btrfs open source effort.
"Technology preview status means we welcome customers to experiment with Btrfs and test it out," Burke said. "But that label really means we are not ready to claim it as an enterprise-ready technology, yet."
On the security front, RHEL 6 includes the System Security Services Daemon (SSSD), which is a new service to manage user credentials and identities.
"SSSD's initial focus is on performance optimizations because there are many programs and applications that will probe for security credentials," Burke said. "SSSD includes the ability to cache network identities. It centralizes identity authentication services and provides a service, which otherwise today is replicated in other system service daemons."
Timeline to GA
With the Beta release of RHEL 6, Red Hat is setting in motion a process that will ultimately lead to the generally available release of the operating system. However, Red Hat is not yet offering a date for when that official release will occur.
"The precise details of the number of betas, the quantity and duration, are not cast in stone -- a lot of it depends on how well things go," Burke said. "At this point, the release is feature-frozen, so we're in good shape where we've landed the features for the release. So at this point, it's a matter of enterprise hardening."
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