RHEL 6 gets its first beta

Massive scale, less virty overhead


The bit twiddlers at Red Hat have been hard at work for the past four years, laying the groundwork in the upstream Linux kernel for what will become Enterprise Linux 6, says Tim Burke, vice president of Linux engineering development at the company. And with RHEL 6, which just entered its first beta today, the company wants to make it cheaper and easier for companies to deploy Linux in their data centers.

With the RHEL 5.5 update three weeks ago, Burke says that the focus was to make that Linux distro compatible with all the new processors coming out this year, including the Xeon 5600 and 7500 from Intel, the Opteron 4100 and 6100 from Advanced Micro Devices, and the Power7 from IBM.

RHEL 5 came out in March 2007 after a six-month beta and release candidate cycle. It started out with the Linux 2.6.18 kernel and has had lots of more current features backported to it without breaking application compatibility as each successive release came out over the past three years. At some point, however, the changes that need to be made to the kernel and related systems software stack are so great that a new version with a new architecture is called for, and such is the case with RHEL 6. Although the two releases will, of course, share some common attributes in terms of scalability and hardware support.

To cook up RHEL 6, Red Hat grabbed a Fedora development release based on the Linux 2.6.32 kernel and hardened it, and then grabbed some of the features that the RHEL engineers deemed were ready for primetime and backported them to that kernel. The main concern with RHEL 6, aside from building in lots of scalability, is to tweak Linux and its management tools so virtualized servers are no more difficult to manage than physical ones, and to remove some of the performance penalties that virtualized servers have to pay.

One big change in the guts of the kernel at the heart of RHEL 6 is that the CPU structures that determine how many physical processors the kernel can span have been made more flexible, thus making it easier for Red Hat to dial up support for increasing numbers of processor cores as chip makers ride Moore's Law. It looks like we'll be getting 50 per cent more cores per year from here on out, on average, because we can’t increase clock speeds any more because of thermal issues, and every operating system has to be ready to absorb that number of cores.

RHEL 6 will have no trouble, laughs Burke, since in theory it has been designed to support up to 64,000 cores in a single system image. And because the way that CPU counts are assigned in the kernel - not with a fixed array that mapped CPU structures to the kernel like in RHEL 5 and earlier releases - it will be relatively easy to make changes as new chips come out.

Ditto for main memory addressability. While RHEL 4, 5, and 6 offer both 32-bit and 64-bit memory addressing, depending on the iron you run it on, the address bits tend to be set a bit lower than 64-bit for physical addressing. With RHEL 5, the theoretical memory limit in the kernel was 46 bits, which yields a maximum of 64 TB of addressable memory. With the RHEL 6 kernel, the theoretical maximum physical memory has been boosted to 48 bits, which yields 128 TB of memory for the kernel and 128 TB for the userspace where Linux applications frolic.

Of course, RHEL 6 has not been tuned to run on a 64,000-core server with 256 TB of memory, not the least of which because it will be at least a few years before such a system is available from Lenovo or Tata. (If you assume 64 sockets maximum and a 50 per cent increase in cores per year, you get to 1,000 cores per chip and 64,000 cores per SMP server in 2022, assuming a linear ramp of Moore's Law.)

"At this point, we have plenty of headroom for CPUs and memory," Burke chuckles. RHEL 5 had a practical memory limit of 1 TB, and RHEL 6 is ready to support the 2 TB main memory being offered on Xeon 7500 and Power7 systems and will scale as the hardware scales.

The KVM hypervisor embedded in RHEL 6 is also getting scalability improvements, which will have larger number of virtualized cores than was possible with RHEL 5 and be able to allocate more CPUs to guest virtual partitions running atop RHEL 6. With RHEL 5, KVM topped out at allowing a guest to address 16 physical processors, and with the initial RHEL 6, this has been quadrupled to 64 physical processors. (When Red Hat says "processor," it means cores, not sockets containing cores or virtual threads inside cores.)

The amount of memory that a KVM guest can address was not at Burke's fingertips when we interviewed him and the release notes that are supposed to be live dead end in a 404 at the moment, so we can't tell you. The original Red Hat Enterprise Virtualization 2.2 hypervisor that is based on RHEL 5 was able have a guest address up to 16 processors and 256 GB of memory, and with RHEL 5.5 that was boosted to 32 processors and 512 GB of memory. It stands to reason that the KVM embedded in RHEL 6 can address 1 TB of memory to match its 64 processors.

RHEL 6 is available on 32-bit x86 and 64-bit x64 processors from Intel and AMD and Power7 and mainframe processors from IBM. As The Register divulged in December 2009, Red Hat is pulling the plug on Intel's Itanium processor support with RHEL 6, much as Microsoft has done with Windows. RHEL 5 will be the last Red Hat Linux to support Itanium (out to 2014 with security patches and updates to support the future "Kittson" and "Poulson" Itanium chips). Microsoft's Windows Server 2008 R2 edition is the last one to support Itanium and will be similarly tweaked to support the two future Itanium chips on the Intel roadmap.

Similar topics


Other stories you might like

  • Screencastify fixes bug that would have let rogue websites spy on webcams
    School-friendly tool still not fully protected, privacy guru warns

    Screencastify, a popular Chrome extension for capturing and sharing videos from websites, was recently found to be vulnerable to a cross-site scripting (XSS) flaw that allowed arbitrary websites to dupe people into unknowingly activating their webcams.

    A miscreant taking advantage of this flaw could then download the resulting video from the victim's Google Drive account.

    Software developer Wladimir Palant, co-founder of ad amelioration biz Eyeo, published a blog post about his findings on Monday. He said he reported the XSS bug in February, and Screencastify's developers fixed it within a day.

    Continue reading
  • FTC urged to protect data privacy of women visiting abortion clinics
    As Supreme Court set to overturn Roe v Wade, safeguards on location info now more vital than ever

    Democrat senators have urged America's Federal Trade Commission to do something to protect the privacy of women after it emerged details of visits to abortion clinics were being sold by data brokers.

    Women's healthcare is an especially thorny issue right now after the Supreme Court voted in a leaked draft majority opinion to overturn Roe v Wade, a landmark ruling that declared women's rights to have an abortion are protected by the Fourteenth Amendment of the US Constitution.

    If the nation's top judges indeed vote to strike down that 1973 decision, individual states, at least, can set their own laws governing women's reproductive rights. Thirteen states already have so-called "trigger laws" in place prohibiting abortions – mostly with exceptions in certain conditions, such as if the pregnancy or childbirth endangers the mother's life – that will go into effect if Roe v Wade is torn up. People living in those states would, in theory, have to travel to another state where abortion is legal to carry out the procedure lawfully, although laws are also planned to ban that.

    Continue reading
  • Zuckerberg sued for alleged role in Cambridge Analytica data-slurp scandal
    I can prove CEO was 'personally involved in Facebook’s failure to protect privacy', DC AG insists

    Cambridge Analytica is back to haunt Mark Zuckerberg: Washington DC's Attorney General filed a lawsuit today directly accusing the Meta CEO of personal involvement in the abuses that led to the data-slurping scandal. 

    DC AG Karl Racine filed [PDF] the civil suit on Monday morning, saying his office's investigations found ample evidence Zuck could be held responsible for that 2018 cluster-fsck. For those who've put it out of mind, UK-based Cambridge Analytica harvested tens of millions of people's info via a third-party Facebook app, revealing a – at best – somewhat slipshod handling of netizens' privacy by the US tech giant.

    That year, Racine sued Facebook, claiming the social network was well aware of the analytics firm's antics yet failed to do anything meaningful until the data harvesting was covered by mainstream media. Facebook repeatedly stymied document production attempts, Racine claimed, and the paperwork it eventually handed over painted a trail he said led directly to Zuck. 

    Continue reading
  • Florida's content-moderation law kept on ice, likely unconstitutional, court says
    So cool you're into free speech because that includes taking down misinformation

    While the US Supreme Court considers an emergency petition to reinstate a preliminary injunction against Texas' social media law HB 20, the US Eleventh Circuit Court of Appeals on Monday partially upheld a similar injunction against Florida's social media law, SB 7072.

    Both Florida and Texas last year passed laws that impose content moderation restrictions, editorial disclosure obligations, and user-data access requirements on large online social networks. The Republican governors of both states justified the laws by claiming that social media sites have been trying to censor conservative voices, an allegation that has not been supported by evidence.

    Multiple studies addressing this issue say right-wing folk aren't being censored. They have found that social media sites try to take down or block misinformation, which researchers say is more common from right-leaning sources.

    Continue reading
  • US-APAC trade deal leaves out Taiwan, military defense not ruled out
    All fun and games until the chip factories are in the crosshairs

    US President Joe Biden has heralded an Indo-Pacific trade deal signed by several nations that do not include Taiwan. At the same time, Biden warned China that America would help defend Taiwan from attack; it is home to a critical slice of the global chip industry, after all. 

    The agreement, known as the Indo-Pacific Economic Framework (IPEF), is still in its infancy, with today's announcement enabling the United States and the other 12 participating countries to begin negotiating "rules of the road that ensure [US businesses] can compete in the Indo-Pacific," the White House said. 

    Along with America, other IPEF signatories are Australia, Brunei, India, Indonesia, Japan, South Korea, Malaysia, New Zealand, the Philippines, Singapore, Thailand and Vietnam. Combined, the White House said, the 13 countries participating in the IPEF make up 40 percent of the global economy. 

    Continue reading
  • 381,000-plus Kubernetes API servers 'exposed to internet'
    Firewall isn't a made-up word from the Hackers movie, people

    A large number of servers running the Kubernetes API have been left exposed to the internet, which is not great: they're potentially vulnerable to abuse.

    Nonprofit security organization The Shadowserver Foundation recently scanned 454,729 systems hosting the popular open-source platform for managing and orchestrating containers, finding that more than 381,645 – or about 84 percent – are accessible via the internet to varying degrees thus providing a cracked door into a corporate network.

    "While this does not mean that these instances are fully open or vulnerable to an attack, it is likely that this level of access was not intended and these instances are an unnecessarily exposed attack surface," Shadowserver's team stressed in a write-up. "They also allow for information leakage on version and build."

    Continue reading

Biting the hand that feeds IT © 1998–2022