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Open Source Operating Systems Upgrades Linux

Linux 3.5 Released 277

Posted by timothy
from the thanks-linus dept.
diegocg writes "Linux 3.5 has been released. New features include support for metadata checksums in Ext4, userspace probes for performance profiling with systemtap/perf, a simple sandboxing mechanism that can filter syscalls, a new network queue management algorithm designed to fight bufferbloat, support for checkpointing and restoring TCP connections, support for TCP Early Retransmit (RFC 5827), support for android-style opportunistic suspend, btrfs I/O failure statistics, and SCSI over Firewire and USB. Here's the full changelog."
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Linux 3.5 Released

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  • Ha ha he he (Score:3, Insightful)

    by Anonymous Coward on Saturday July 21, 2012 @07:57PM (#40726535)

    It's funny. The Linux community put so much effort into trying to win the OS of the Desktop with so little success, but secretly won the battle of the OS on phones and tablets with hardly a fanboy.

    • Re:Ha ha he he (Score:5, Insightful)

      by Teresita (982888) <`badinage1' `at' `netzero dot net'> on Saturday July 21, 2012 @08:13PM (#40726615) Homepage
      Desktops were locked down under the Microsoft Tax, Linux never had a chance. Along comes another platform, and it was Microsoft left flapping in the wind.
      • Re:Ha ha he he (Score:4, Insightful)

        by Kjella (173770) on Saturday July 21, 2012 @08:30PM (#40726703) Homepage

        Desktops were locked down under the Microsoft Tax, Linux never had a chance. Along comes another platform, and it was Microsoft left flapping in the wind.

        As usual it was Apple coming in doing something people have done before, only much better. I remember Microsoft tablets, there's no doubt they were first - and unusable. It was just like a PC, except with a stylus instead of a keyboard which we all know is so efficient. Lately I've been a bit surprised though because Apple has taken real technological leadership in some areas, like the display on the iPad 3 and the retina MBP. Things where you can truly say that there hasn't been anything like that offered ever before. Makes me both want to love their gear and hate their walled in garden.

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          The display in the Macbook Pro isn't produced by Apple.

          • Re:Ha ha he he (Score:4, Insightful)

            by jones_supa (887896) on Saturday July 21, 2012 @09:45PM (#40727051)
            Yes, but Apple has the power to choose the components, which makes a difference to what we see on the marketplace.
          • Re:Ha ha he he (Score:4, Insightful)

            by larry bagina (561269) on Saturday July 21, 2012 @10:12PM (#40727151) Journal
            There are three parts to retina graphics. 1. Is the hardware. Apple doesn't manufacture it, but they do select it. 2. Is the Operating system. The physical pixels double but the virtual pixels stay the same and the OS displays double-sized (@2x) images if available or pixel-doubles existing image (and they look like a bag of ass). 3. is the software -- it needs to provide double-sized (@2x) images.

            Samsung or Dell can use a high-DPI screen but they're limited on OS modifications and convincing third party software to support it. Maybe android is better about scalable graphics, but Apple still has the advantage of synchronizing the hardware and software.

            • Re:Ha ha he he (Score:5, Interesting)

              by ZosX (517789) <zosxavius AT gmail DOT com> on Saturday July 21, 2012 @10:57PM (#40727317) Homepage

              Android scales graphis just fine IMO. if you run something like an older game that was designed for a lower dpi device, it just scales it. Generally you have the option to allow it to run smaller in its native resolution as well. Many of the android games use vectors for sprites, so asides from backgrounds looking pixelated, the sprites generally look pretty decent. I dunno, I went from a phone with an 800x480 display to a tablet with a 1280x800 display. If you ask me, android, at least ICS and beyond, handles high resolutions very well. It will scale the UI to match the dpi of the phone. I don't think apple has any real advantage here.

              • Re: (Score:2, Informative)

                by cheesybagel (670288)
                Android not only supports different resolutions but also different aspect ratios. There is a reason why Apple keeps selecting the same aspect ratio over and over again...
                • Re: (Score:3, Informative)

                  by Anonymous Coward

                  How the fuck did this get modded "insightful"? iPads and iPhones already have different aspect ratios (1.33 vs. 1.5).

                  • Re:Ha ha he he (Score:4, Interesting)

                    by makomk (752139) on Monday July 23, 2012 @07:15AM (#40734933) Journal

                    The iPad has a different apect ratio from the iPhone, but that means that every existing application needed to have iPad support added explicitly in order to work well. Apple managed to get away with that since phone app UIs don't tend to scale too well on a 10-inch tablet anyway.

                    Every iPhone still has the same aspect ratio as the original iPhone and every iPad the same as the original iPad, though. Not only that but Apple had to delay increasing the resolution of their devices until they could get displays with double the pixel density, whereas Android manufacturers could use intermediate screen resolutions, and apparently driving all those pixels has been killing battery life and GPU performance.

              • Re:Ha ha he he (Score:4, Insightful)

                by DrXym (126579) on Sunday July 22, 2012 @12:19PM (#40730093)
                Android support different resolutions just fine, but as a developer I can tell you what a gigantic pain in the ass this is. Layouts may look fine in one layout or resolution and terrible in another so you spend an inordinate amount of time fine tuning them to cope, or you multiply your pain by implementing specific layouts for specific device formats. When tablets turned up, the existing ldpi, mdpi, hdpi model proved inadequate so Android lets you write layouts that only fire when resolution is horizontally greater than some amount or other criteria but this only works in 3.x+. There are things you can do to keep the pain down (e.g. decompose layouts so you can reuse stuff) but it's still pain. Testing time also increases since you must test frequently in different devices and profiles to ensure it works.

                You can get a flavour of the pain by reading what Google suggests [blogspot.ie] to make apps run on the Nexus 7.

                Apple has the advantage of owning the hardware and the software so there are a fix number of resolutions to support. I think if they start producing half-way house designs like larger iPhones or smaller iPads that they'll run into the same problem.

            • by epyT-R (613989)

              increasing display resolution by itself isn't new technology, nor is it apple specific. personally i'd prefer having more desktop space, but I guess most people are too blind to handle anything 'virtually' larger than 1440x900..

            • Matt Blaze tweeted that Apple doesn't support the full resolution of the Retina display on the MacBook - the most you can set is 1920x1200, and it scales it from there. He also reports that there's a workaround [9to5mac.com] which will let you get the full resolution.

              But still, SRSLY? You'd think Apple could get font scaling correct, especially since they've been selling big desktop displays for years.

              • Kinda off subject here, but ...

                Your standard app was not written for silly-high DPR. You could show this on linux too: take your desktop, and crank the DPI to 300 or so, so that the X server thinks your screen is only 5" across. Now move far enough away from it that a 12 point font looks reasonable, and then look at how stupid apps look. Icons are microscopic (because they're defined in fixed pixel sizes). Layouts between menubars and borders look stupid (natural spacing was defined in fixed pixel sizes).

                So Apple's approach here is to tell the application that the screen is 1440x900. Any primitives that can be scaled ("place the string 'pants' in font 'Helvitica', size 12pt, at X,Y". "Draw this 2kx2k pixmap in this 500px x 500px space") are then rendered to the screen's native resolution. Things that can't be scaled aren't ("draw this 96x96 pixmap here, in this 96x96 space"). Some apps then look horrible, some look great.

                I personally would have rather they just let apps look like crap, and told people to fix their darn apps, but I can understand why they didn't.

                • by shutdown -p now (807394) on Sunday July 22, 2012 @08:20PM (#40732573) Journal

                  I personally would have rather they just let apps look like crap, and told people to fix their darn apps

                  Microsoft has had 20 years of track record with this approach, and the results are meh. Eventually Vista had to change the rules by requiring the apps to tell the system whether they are DPI-aware, and if they don't do that (e.g. all old apps), do bitmap scaling on them. Even so there are still quite a few apps written after Vista which do tell the system that they are DPI-aware, but then don't properly handle anything but the default 96 DPI.

              • by exomondo (1725132) on Sunday July 22, 2012 @11:25PM (#40733457)

                But still, SRSLY? You'd think Apple could get font scaling correct, especially since they've been selling big desktop displays for years.

                That still annoys me about OSX, you can't set the system font size.

        • by epyT-R (613989)

          and if you buy that gear, you support their garden of eden. knowledge is verboten.

        • I remember Microsoft tablets, there's no doubt they were first...

          Except they weren't [wikipedia.org], maybe you mean "they came before". Microsoft Windows for Pen Computing was a ripoff of GO's PenPoint from 1991, right down the the notebook metaphor in their promotional slides. PenPoint launched on tablet computers from IBM and NCR before Microsoft was able to cobble together their first demo. And before GO there were attempts such as Pencept and Momenta to interact with an LCD screen with a tethered pen.

          - and unusable

          Stylus computing works great for annotating existing content (cue AT

        • by gbjbaanb (229885)

          I remember Microsoft tablets, there's no doubt they were first - and unusable. It was just like a PC

          and now, with Windows 8, we have tablets that are just like the PC... only now its the PC that's unusable :)

      • Re: (Score:3, Insightful)

        by cpu6502 (1960974)

        Linux would still have failed if it had not been backed by google. Right now we'd all be discussing Apple iOS and Microsoft's Windows Phone, plus some ubuntu-derived distribution that only the engineers know how to install on their phone.

        BUT along comes Google and they used their resources to make Android Linux a success, by selling direct to manufacturers. Now we just need Google to consider porting Android to AMD/Intel desktops.

        • by siddesu (698447)

          Now we just need Google to consider porting Android to AMD/Intel desktops.

          Android runs fine on x86. You can even download it and compile it yourself, if you're into that kind of BSDM.

          • by ZosX (517789)

            yeah, but will all the arm optimized apps that run native code work? android on mips faces the same problem.

            • by siddesu (698447)
              All apps I've tried worked okay. Even hardware extras like bluetooth and USB storage get recognized without any problems. Maybe I simply haven't hit any apps that use native libraries, but then I think very few do.
            • No, they have to be rebuilt for Intel.

            • As I recall, ever since Intel had started pushing its x86 chips for mobile (Medfield for phones and Clover Field for tablets), they've put a lot of attention to this problem, and teamed up with Google. IIRC, if you're using a recent Android NDK, and try to build something, it's set up to build and package x86 binaries by default. They also have binary translation implemented, akin to Rosetta, though I don't know if there's some hardware component to it such that it might not work on your random desktop Inte

        • Re:Ha ha he he (Score:4, Insightful)

          by sjames (1099) on Saturday July 21, 2012 @10:42PM (#40727247) Homepage

          Of course, IOS would have failed were it not backed by a big pile of corporate cash as well.

        • Android already runs on Intel, but it would take some work to make the UI work properly for the desktop.

          However, at this point Google is more interested in making Chrome OS the desktop OS.

        • Re:Ha ha he he (Score:5, Insightful)

          by Runaway1956 (1322357) on Sunday July 22, 2012 @12:05AM (#40727623) Homepage Journal

          You have one way of looking at it. Some of us have another view of the matter.

          Anyone who does NOT want to rely on Mac or Microsoft, is going to choose - what, exactly? There are several Unix-likes out there, so Linux isn't a shoe-in. What is it about Linux, that made Google choose it over any other Unix-likes?

          My money is on the pervasive GPL. The GPL fits Google's agenda better than any other licensing scheme, and that's pretty much the end of that story.

        • Re:Ha ha he he (Score:5, Insightful)

          by Teun (17872) on Sunday July 22, 2012 @04:05AM (#40728435) Homepage
          Without Android the Nokia version of Linux might have taken off quite well.
          There were and are plenty of consumers not endeared to the Apple ways and MS was never a contender.

          Considering Nokia stopped official development of their Linux system around the time of their engagement with MS the N900 and N9 are even now still remarkably useful phones.

        • Re:Ha ha he he (Score:5, Interesting)

          by gbjbaanb (229885) on Sunday July 22, 2012 @10:14AM (#40729541)

          Linux always succeeded - only not anywhere you can see it.

          Linux still runs 80%+ of the world's internet, Linux runs a vast majority of embedded devices. This is the reason Google got into it - it already was there when Google appeared and started to think "what web OS do we use for our HPC system" - it was pretty obvious to them to use the market leader in those arenas - Linux - and when they decided to go for an embedded phone device, they again chose the market leader in that area - Linux.

          Linux made Google big, not the other way round.

      • the politics of old school Unix hackers. It is the kind of politics that keeps distros from really standardizing on a GUI, and also results in oddities like the Linux Foundation having an SDK for mobile, but none for desktop. Likewise, Android has an SDK but Ubuntu (and all the other desktop distros) do not.

        • by MrHanky (141717)

          It's got nothing to do with politics, people with different preferences just happen to build different things.

          • by Anonymous Coward on Saturday July 21, 2012 @09:34PM (#40727017)

            That is fundamentally what politics is about: getting people who want different things to act together in a useful way.

          • by Burz (138833) on Sunday July 22, 2012 @12:31AM (#40727731) Journal

            It's got nothing to do with politics, people with different preferences just happen to build different things.

            Politics are about group preferences and group identity. It's got a heck of a lot to do with politics: There's no rational reason to offer standardized frameworks under an SDK for mobile, but avoid doing so for desktops. One of the irrational reasons behind the disparity is that the hacker and sysadmin culture view PCs as immediate kin to web servers hardware and regard any standardization or vertical integration in the stack that caters primarily to "luser" needs as a threat to their freedom and efficiency.

            The overall 'distro' mindset causes each and every initiative to become hamstrung with idiotic assumptions, such as:

            - Each application should be broken down into between 2 - 20 different pieces and scattered around one's hard drive.

            - Changes for most system components are handled in exactly the same way and with the same priorities as high-level applications, and apps get to make dependency demands on the inner workings of the system. There is no clear distinction between system and apps for anything being updated, added or removed.

            - Anything other than the kernel = "application", and this type of system-hacker nomenclature must be observed by everyone or they will be ridiculed as 'n00b'. The result is a kind of blindness to real issues that arise around interactions between apps and system.

            - System coders > App coders, so we will just get Miguel and some of the ol' gang to whip up some applications that will put Microsoft and Adobe to shame (i.e. we'll draw from the pool of Linux system enthusiasts to write user-facing apps instead of creating a feature-stable environment with an SDK to attract both newbies, and experienced app coders who are only newbie to 'our' system). But the reality is that the particular hacker culture and general feature-instability act as a corrosive acid against the kind of userbase and developer community that a personal computer needs.

            - More than 10 people like to manage their PC software within a paradigm designed for servers.

            - Fewer GUI admin tools are better b/c people will just want to hit the CLI anyway. Avoid the GUI when describing solutions, even WRT office/productivity if possible.

            - A myriad different admin tools for basic network connectivity are OK because people want 'choice' (esp. when they call up tech support for their ISP or application and the technician can't figure out what specific steps to tell the user).

            - Each year, desktop users must learn to recognize "Linux" by the current and past iterations of the 4 or 5 desktop environments that are officially supported by each distro.

            - App developers like to design their apps for a disembodied desktop environment, instead of viewing the OS layers underneath as equally accessible tools. They also like testing their app in several other desktop environments to ensure that it "plays well" with them.

            - App devs love having to test and package on multiple distros, and they look forward to having many camps of distro maintainers telling them about app "bugs" that mean you have to help them fix the same issue in their systems over and over again for a number of years. They also love having maintainers pepper and berate them over wacky compile switches, setting defaults, patches, etc. and they way they like to refer to app devs as "upstream" instead of "author", as if "Linux" coding automatically entailed some sort of demotion.

            - If one is an ISV (distributing a proprietary app as 3rd party), devs love being regarded as an oddball instead of the norm, and love being reminded constantly that so many of the compatibility issues with (untargetted) distros they keep having to read about could be automatically resolved if, gosh, the author would only release their app as open source so they could be merged with repository nirvana.

            - App devs love hearing they should leave behind all the PC stuff and

            • by Doctor_Jest (688315) on Sunday July 22, 2012 @02:29AM (#40728109)

              It's funny, I've got a generic Dell PC I got for $300 from their outlet (Athlon etc etc.) Not a powerhouse, but not a shrinking violet either. I used my Mac Mini to download Debian Squeeze... and in 2 hours, with less interaction than a Windows install... I had a completely functional Linux desktop PC without doing anything in your list, except pick Debian. Back in college, I never got my et4000 card settings right for X on Slackware 0.99 (on floppies no less), but with screen and a familiarity with Amiga's CLI and DOS... I didn't miss it. (Plus that is the first time I got hooked on Nethack...)

              Now, in the dim past just about everything was more difficult, to be sure... Getting games to run in DOS was also a magic trick. Then there was the myriad of other things that the CLI (which is where the computer originated) made easier for some, harder for others. Hell, Windows had a devil of a time keeping stable with the myriad of 3rd party drivers out there for Video and Sound cards alone.... Let's not forget NICs and so forth... And let's not diminish the fact that Windows used to be a graphical shell over DOS... for many years it was "hiding" DOS from the user...

              Linux is a tool not everyone should use. There are idiots who shouldn't use a computer too. The fact that Linux has thrived in spite of Windows and Macintosh speaks more about the users and developers than it does about the drones who buy iPads and iPods because they're "hip". Those people don't use computers... they use appliances.

              Here's a tip, though... if you hide everything from the user (a 'la original MacOS and returning to that I might add) it doesn't make them better at using a computer... it just makes them think all computers are magic. Which, in some people's case... I think should remain that way. :)

              • Re: (Score:2, Interesting)

                by Anonymous Coward

                Here's a tip, though... if you hide everything from the user (a 'la original MacOS and returning to that I might add)

                They're not really hiding anything these days. They're mainly locking everything down, which is much worse. And fwiw, the original Mac OS didn't hide that much. You had to use ResEdit rather than emacs or vim to look at the internals of most stuff, but it's not like the average user knows what the /etc directory is, let alone what to change there (or even how to get sudo rights to do so, if the editor doesn't contain built-in functionality for that)

                One big problem with classic Mac OS was that everything was

            • by Anonymous Coward

              Linux pretty much kicks ass if you're an engineer though, because all of the things that make it horrible for end users give you enough access to pick your project apart down to assembly.

        • What do you mean? (Score:5, Informative)

          by billstewart (78916) on Saturday July 21, 2012 @11:36PM (#40727507) Journal

          Back when I was running X Windows versions 10.x and early 11s, there was no requirement that I use TWM. And while the Sun 2 came with SunView, the Sun 3 could run either SunView or X, and you could get Grasshopper Group's implementation of NeWS if you preferred, which drove your screen in Postscript. Among other things, that meant that if you wanted to change the font size to match the size of your monitor and your eyesight, you just did it, and What You Saw Was What You Wanted. None of this "need a third-party developer's hack to use the full resolution of the expensive Retina Display you just bought" nonsense. But even if you were running X, you weren't limited to Motif or OpenLook; you could run whatever window manager you liked with it.

          As far as "Ubuntu [does] not [have an SDK]" goes, you can use the Gnome SDK or KDE or LXDE or several other fairly full-featured SDKs.

      • by roc97007 (608802)

        I think Microsoft to a certain extent left themselves flapping in the wind, by pursuing late, and insisting on pushing a desktop paradigm on other devices even when it's apparent that it wasn't a good fit. They seemed to think that "it's Windows" was a good enough selling point that it didn't have to be useable. And that allowed other approaches to run away with the market. Even with Windows 8, they're still insisting on the same interface everywhere, this time, it appears, by dumbing down the desktop, i

    • by mikael_j (106439)

      There are plenty of Linux "on phones and tablets" fanboys. They are sometimes derisively called "fandroids". And some of them are quite obnoxious...

      • Re: (Score:3, Funny)

        by TwinkieStix (571736)

        A group of people inside of a sub group of a subgroup are quite obnoxious. Sounds like some Slashdot commenters. Wait.

    • Re:Ha ha he he (Score:5, Informative)

      by El_Oscuro (1022477) on Saturday July 21, 2012 @09:23PM (#40726955) Homepage
      Also on ereaders. According to Wikipedia [wikipedia.org], almost all of the major brands run Linux.
    • Any ideas when Ubuntu will support the 3.5 kernel? Real Soon, or not until 12.10?

    • Yes, I agree... our Android vs iOS discussions are impressively civil!

    • Re:Ha ha he he (Score:5, Interesting)

      by sonamchauhan (587356) <sonamcNO@SPAMgmail.com> on Sunday July 22, 2012 @03:49AM (#40728385) Journal

      The Linux desktops of old got transformed into Linux server, were gratefully used by Google for their server infrastructure.

      Then, as mobile phone hardware began to resemble the desktops of yesteryear, Google went "hmmmm..."

      And so it flows.

  • by twistedcubic (577194) on Saturday July 21, 2012 @08:00PM (#40726549)
    Now this looks interesting. Hopefully it works as described on the net (http://lwn.net/Articles/479841/). Automatic suspend would be wonderful.
  • even though i'm logged in, kernelnewbies page says "Immutable Page" - so maybe somebody with write privs can fix "makes impossibles" ;)

    • I'll have a word with Sergei.

      • by macemoneta (154740) on Saturday July 21, 2012 @08:27PM (#40726689) Homepage

        Btrfs is stable enough for real data, if you run current releases (latest 3.4 or 3.5 kernel and btrfs-progs-19 current). I use it in both single drive systems and raid1 configurations with Fedora 17. Prior to converting the systems, I ran extensive failure testing (e.g., pulling power / data connection during active writes, system crashes, using a failing drive with media errors as part of a raid1, etc.) for about a month. I never lost a single byte of data in any test, confirmed by checksum scans on all data (against a backup) after each test cycle.

        I actually trust btrfs now more than ext4 due to the ability to scrub the data and confirm integrity, which I do daily or weekly depending on the system.

        • wow. I'm still using 2.6.37 (OpenSuSE 11.4 vm image). What can I say, it ain't broke so I've never bothered fixing it :)

          • It depends on your definition of 'broke'. You don't have any of the functionality in the newer kernels (tens of thousands of patches to current), so if you want to use any of that it certainly is 'broke'. :)

        • What about performance? I tried btrfs on an older machine (Pentium 3), a few kernels ago, before the recent big performance improvements. Firefox didn't do so well on a btrfs partition. It was the second biggest CPU hog, after the btrfs processes. Switching back to ext4 was a big improvement.

          • by macemoneta (154740) on Saturday July 21, 2012 @08:53PM (#40726827) Homepage

            With the current implementation and just the 'autodefrag' option added to default, there is no perceptable difference in performance compared to ext4 for any of our machines, with any application. Recent testing at Phoronix (with 3.4) has btrfs getting closer to ext4 (running without lvm2 and md raid); I'm curious to see how its numbers look in 3.5. However, because btrfs integrates the functionality of lvm2 and md raid in a much more usable manner, as well as providing much more functionality, a small performance tradeoff would be acceptable (to me).

  • by Peter H.S. (38077) on Saturday July 21, 2012 @08:04PM (#40726575) Homepage

    Ext4 metadata checksums. I like that. Note that it isn't data CRC checksums, just metadata. Still, I like the way Ext4 keeps evolving and getting tuned. Btrfs sounds really great, but it may still be some time before it is stable enough for my data storage needs.

    • by macemoneta (154740) on Saturday July 21, 2012 @08:29PM (#40726697) Homepage

      I accidentally replied to the wrong thread. Repost:

      Btrfs is stable enough for real data, if you run current releases (latest 3.4 or 3.5 kernel and btrfs-progs-19 current). I use it in both single drive systems and raid1 configurations with Fedora 17. Prior to converting the systems, I ran extensive failure testing (e.g., pulling power / data connection during active writes, system crashes, using a failing drive with media errors as part of a raid1, etc.) for about a month. I never lost a single byte of data in any test, confirmed by checksum scans on all data (against a backup) after each test cycle.

      I actually trust btrfs now more than ext4 due to the ability to scrub the data and confirm integrity, which I do daily or weekly depending on the system.

      • by dAzED1 (33635)
        I've been in a couple Fedora FUDs, and I'm running Fed17 while typing in this little box thing to reply to you. That said...."real data" isn't stored on a box running Fedora. Sorry. I mean that with lots of love to the entire Fedora community (well...most of it...) but...I'm pretty sure most of the community wouldn't claim it's a production server OS anyway.
        • You may be surprised to learn that the definition of 'production' is very much locally defined. To some companies I've dealt with, ancient stable software that gets no maintenance for years is the way to go. To others, driving the leading edge means competitive advantage. Most fall somewhere in the middle.

      • by Teun (17872)
        Since around February a run one /home on btrfs and have not seen any issues.

        At the same time I also installed / on it but then found out it is not yet supported during Grub updates.

        • Grub2 (I'm using grub2-2.0-0.37.beta6) supports a btrfs root (/). I have two machines running that way.

          • I wonder what's the fascination in running btrfs on /.

            The benefits of btrfs are in large partitions and places wheredata changes are both critical and frequent. I don't see that in / on any sane system.

      • by Peter H.S. (38077)

        It is not that I doesn't drool over Btrfs. I also think it is very stable, but if the Fedora committee decided that Ext4 was the default FS for F17 I think it is better for me (who doesn't compile my own kernel any more, but a cheer to those that still do that like you) to wait for at least Fedora 18.

        And advanced filesystems are really really hard to get right, I will be really surprised if some corner case bugs doesn't show up when Btrfs is deployed on a large scale. There is also the various support tools

  • Anyone knowledgeable can tell me what is "checkpointing and restoring TCP connections"?
    • Re: (Score:3, Informative)

      by Anonymous Coward

      It's a way of transferring TCP connections to another server (along with transferring the IP address). That way, you could do hardware maintenance on the physical machine without losing anything because you've migrated it seamlessly to another machine. Of course, you have to transfer and restore everything else over too (running processes, memory, etc).

    • by sjames (1099) on Saturday July 21, 2012 @11:10PM (#40727383) Homepage

      It's part of the larger project for process/system checkpointing in general.

      That is, saving the entire state of a process to storage such that it can start up again where it left off and not know the difference.

      • by manu0601 (2221348)

        saving the entire state of a process to storage such that it can start up again where it left off and not know the difference.

        But what is the point to save and restore a TCP state? While local endpoint sleeps, the remote endpoint does not receive any reply. After a while it will reset the connexion, and the local endpoint will not even know. Or is it just for connexions to localhost?

        • by sjames (1099)

          The only case I can see is for things like MPI where both endpoints of the TCP connection are being checkpointed at the same time.

  • by dnaumov (453672)

    So, is this thing finally usable in production or is everybody who actually cares about data still stuck with ZFS?

    • Re: (Score:3, Informative)

      by jarfil (1341877)

      I've been using BTRFS in production since 3.3.1 with zero problems.

      Before that, I did experience a partial fs meltdown on 3.2.x while stress testing a high number of snapshots with several million files/dirs and intense db activity. Then, the same test on 3.3.1 went flawlessly.

      So I wouldn't recommend using BTRFS with anything below 3.3.1, but 3.4 or 3.5 should be fine.

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