Novell is out today with its first major update to its SUSE Linux Enterprise 11 operating system. SUSE Linux Enterprise 11 Service Pack 1 (SP1) does at least one thing differently than Novell has done in the past with updates for SUSE Linux Enterprise Server (SLES) 9 and 10: It introduces a new Linux kernel.
When it comes to enterprise Linux distributions, maintaining compatibility throughout a version release is critical for software and hardware vendor support. That's why enterprise Linux vendors including Novell and Red Hat typically retain the same Linux kernel version number throughout the entirety of an enterprise release like SLES 10 and backport features from newer kernels. Novell is now breaking that mold with SLES 11 SP1, in an effort it says will provide more functionality while maintaining compatibility.
"There were some things that led us to update the kernel itself, which is something that we normally don't do: Neither SLES 9 or SLES 10 got a kernel update," Markus Rex, director of open platform solutions at Novell, told InternetNews.com. "But in this particular case, after deep discussion with our ISV and hardware vendors that gave us certifications, we felt in this case a kernel update was the appropriate step to take."
"The biggest thing is that, as a server operating system, we have to make sure that we run on the appropriate server chips," Rex said. "So the key decision factor for us was that we wanted to make sure we supported the newest hardware to the maximum capabilities."
With the newer kernel, SLES 11 SP1 is getting hardware enablement for the latest Intel Westmere chips as well as additional Linux scheduler improvements.
Rival Linux vendor Red Hat recently updated its Red Hat Enterprise Linux (RHEL) operating system to version 5.5. RHEL 5.5 also includes support for the latest Intel chips, however, Red Hat did not rebase its Linux kernel version. Instead, support was backported in an effort to preserve ISV compatibility.
But Novell sees its approach -- rebasing the Linux kernel in SLES 11 SP1 -- not affecting its own ISV certifications.
"We looked at the current application certification portfolio and we contacted all of our ISVs and verified and confirmed whether the changes we were making would actually be breaking compatibility," Kerry Kim, senior product marketing manager at Novell told InternetNews.com. "What we discovered is that, for many ISVs, the userspace application compatibility was persevered and the changes to the APIs didn't change their certification status."
With the newer Linux kernel, Novell has also advanced the EXT4 Linux filesystem to a fully supported technology. When SLES 11 was first released, EXT4 -- which provides new filesystem scalability and performance features -- had been considered only a technology preview. At the same time, Novell is also including the next-generation BTRFS filesystem as a technology preview.
Xen, KVM Virtualization Update
In addition to the kernel update, Novell also has updated the Xen virtualization engine in SLES 11 to the Xen 4 release. As was the case with the kernel update, Novell checked with its ISV partners to ensure that the new Xen release would not break backwards compatibility with SLES 11 Xen 3 deployments.
Novell has also updated some virtualization components in KVM -- a Xen rival in virtualization technology -- as part of the SP1 update.
"For the lifetime of SLES 11, there will absolutely be a dual future with KVM and Xen," Rex said. "When we look at the time it took for Xen to stabilize, it was quite a while, and KVM is a little younger than Xen. While I have no concerns about the stability of KVM, the userbase still has to get used to a different hypervisor compared to the model that they have been used to with Xen."
Novell's Rex said that while he's confident that having both Xen and KVM is the right way to go for SLES 11, Novell has not yet determined what the direction will be for SLES 12 in the future.