back to article Already in final beta? That's Madagascar: Ubuntu 20.04 'Focal Fossa' gets updated desktop, ZFS support

Canonical has dropped a final beta of Ubuntu 20.04 "Focal Fossa", set for full release on 23 April. Ubuntu has a six-monthly release cycle, with a long-term support release every two years. Ubuntu 20.04 is one of those, so this will get hardware and maintenance updates until 2022, maintenance updates until 2025, and extended …

  1. _LC_ Silver badge
    Stop

    ZFS is for dedicated file-servers

    I feel the obligation to tell the people that ZFS is only useful on dedicated file-servers (as Ubuntu is unlikely to be used for those). Some people read the specs and decide to run ZFS on their desktop systems. That is stupid in many ways. Do yourself the favor and don't.

    1. bazza Silver badge

      Re: ZFS is for dedicated file-servers

      Surely you're not hinting that they should use btrfs instead?

      Software package management is heading towards using ZFS snapshots. It'll be the way you get software, or uninstall it. It's a pretty neat idea.

      There's many features of ZFS that are highly attractive to desktop usage. It's far, far more flexible for different storage requirements inside a single machine than something like the (venerable but certainly respected) ext filesystems, and why wouldn't a desktop user want flexibility in how their disparate data types are stored?

      1. John Brown (no body) Silver badge

        Re: ZFS is for dedicated file-servers

        "Software package management is heading towards using ZFS snapshots. It'll be the way you get software, or uninstall it. It's a pretty neat idea."

        Can you elaborate further please? AFAIK you snapshot a filesystem, not a file or files. As ZFS currently stands, there is no way to use it as a package manager unless you only ever return back to a fixed point, "uninstalling" every package installed after the last snapshot. You can install Gimp one day, install Libreoffice the next and then go back and uninstall Gimp without uninstalling Libreoffice. ZFS just doesn't work like that.

        1. Anonymous Coward
          Anonymous Coward

          Re: Behind their 'paywall'

          From memory when upgrading the utility snapshot the filesystems in the root volume group, do the upgrade, reboot into the snapshot.

          Wanna rollback the update, reverse the process.

          That's how it works on Solaris-ZFS (its called Boot Environments) and it works extremely well.

          Its been a few years so I might be rusty on the detail and its update management rather than package management but I can see it working for that too.

    2. jason_derp Bronze badge

      Re: ZFS is for dedicated file-servers

      "That is stupid in many ways. Do yourself the favor and don't."

      Could you elaborate please?

      1. TechnicalBen Silver badge

        Re: ZFS is for dedicated file-servers

        AFAIK the makers/designer of the ZFS systems say... don't use it. But that may have changed now with progress and feature additions.

        But "support" =/= "boot drive" or the grub etc nessisarily. Though it might be possible now.

      2. Degenerate Scumbag

        Re: ZFS is for dedicated file-servers

        For one, it eats memory like no other filesystem. The projects itself states that it can be used with 2GB, but 8GB+ is recommended for decent performance. The consensus among major users seems to be 8GB + 1GB per terabyte of storage. Of course, this is for caching, and you could argue that Linux itself allocates unused memory as disk cache whatever the filesystem, but ZFS being non Linux-native code bolted on to the kernel is not plumbed in to that system. It allocates that cache memory to itself like application memory. None of this is a problem in it's intended application, but it's hardly optimal for desktops.

        1. Anonymous Coward
          Anonymous Coward

          @Degenerate Scumbag - Re: ZFS is for dedicated file-servers

          To down-voters: it would be useful to many of us to know why you consider what the poster believes is wrong or incorrect. If you know something we don't know, please don't keep us in the dark.

          1. bazza Silver badge

            Re: @Degenerate Scumbag - ZFS is for dedicated file-servers

            It works, is widely used, and has features like nothing else. Other attempts to match it have not succeeded. It does use chunks of memory, but then so would anything else doing the same job. And it's not like PCs are stuck with small amounts of RAM these days. There are unresolved licensing vaguenesses w.r.t. GPL2 (Linux) - but it's clearly alright for individuals to integrate it with their own Linux installations. Other open OSes have no problems with its license.

            Saying, "don't use it", is like saying, "make do without its unique features" and isn't offering a viable alternative. Like it or not, Sun did do an excellent job of thinking anew about what storage had to do. People are using it because, yes, they've read the specs and can't really get those features from anything else. The reason why Ubuntu are going out on a slight limb is that they're responding to demand.

            1. Degenerate Scumbag

              Re: @Degenerate Scumbag - ZFS is for dedicated file-servers

              >It works, is widely used, and has features like nothing else. Other attempts to match it have not succeeded.

              This is true, in the context of its designed purpose.

              >It does use chunks of memory, but then so would anything else doing the same job.

              The job it's designed for is to be a dedicated storage server, and it uses memory accordingly. It intentionally gobbles up all available system memory, leaving just a small headroom for safety, and unfortunately because it wasn't designed with the Linux kernel architecture in mind, it's not plumbed into the regular kernel disk cache system, and thus won't release that memory as instantly as a native Linux filesystem does.

              >Saying, "don't use it", is like saying, "make do without its unique features" and isn't offering a viable alternative.

              The OP was advising against using it in inappropriate applications. For all you know they could be a big fan of it in the proper context, as am I. And of course, I'm sure we'd all like to see a similarly functional Linux-native equivalent COW filesystem created, that would play better with the Linux kernel and be suitable for more general applications. (With BTRFS seemingly at a dead-end, Bcachefs is the new hope on that front.)

              And talking about its unique features, I'll refer back to your earlier comment:

              >Software package management is heading towards using ZFS snapshots. It'll be the way you get software, or uninstall it. It's a pretty neat idea.

              The experimental ZFS snapshot functionality that Ubuntu have implemented in package management is merely a "roll-back" feature, ie make a snapshot before applying changes, so it can be reverted to the known good state if things go wrong. This is conceptually similar to what Windows does with "System Restore", by creating restore points before applying updates.

              The idea that ZFS snapshots could be used to distribute software betrays a fundamental misunderstanding of the concepts involved. ZFS snapshots are a filesystem block-level feature, and thus a snapshot is only applicable to the ZFS filesystem it came from, or a replica of it.

          2. This post has been deleted by its author

        2. bazza Silver badge

          Re: ZFS is for dedicated file-servers

          For one, it eats memory like no other filesystem. The projects itself states that it can be used with 2GB, but 8GB+ is recommended for decent performance. The consensus among major users seems to be 8GB + 1GB per terabyte of storage.

          To be fair to Ubuntu they are only experimenting with ZFS on the desktop at present. They must be pretty confident of striking a good balance between performance and RAM consumption. It's probably a safe assumption that those wanting to use ZFS for its features are in the "power user" camp, and likely have a stack of RAM installed already.

          Also, wait a couple of years and 8GB is going to look like a surpassingly trivial amount of memory. This might mean that Ubuntu are doing this at the right time, when machine specs are moving into the area where no one would care. Ubuntu should be just about finished experimenting by then.

          1. Warm Braw Silver badge

            Re: ZFS is for dedicated file-servers

            I have a machine on which I run a bunch of virtual servers - by the time you get enough RAM for that, the additional memory you need for ZFS is relatively insignificant and it buys you a lot in terms of data security and flexibility. I haven't up to now being using it on the root file system, but this sounds like the ideal opportunity to do it.

            1. Bronek Kozicki Silver badge

              Re: ZFS is for dedicated file-servers

              I'm in the same position and I struggle to understand why anyone would downvote you for this. Also considering switching the minimalist hypervisor Linux installation which is running this box, to boot from ZFS instead (it is booting from ESP partition now)

        3. Bronek Kozicki Silver badge

          Re: ZFS is for dedicated file-servers

          4GB is good, for relatively small machine. I am using this in one of my VMs with this much RAM and it works fine (actually, it is ZFS nested inside ZFS volume which is owned by the hypervisor).

        4. Tom 38 Silver badge

          Re: ZFS is for dedicated file-servers

          File server, database server, desktop - you always want your disk cache to use all your available RAM. ZFS does use a separate cache from the default linux block cache, but if you are using only ZFS or ZFS + small boot drive, that's not really relevant, its not putting things in to both block cache and ZFS's cache.

          ZFS's cache is called ARC (Adaptive Read Cache). If you really want to, there is one tunable to set to control the maximum size of your ARC, however (as the name suggests), its an adaptive cache - with pressure it will adapt and shrink as you require more RAM for applications.

          If you have spinning disks and want to accelerate reads from them, you can attach an SSD and tell ZFS that this is an additional cache - a Level 2 ARC (L2ARC) - and anything that gets ejected from ARC will be written to L2ARC.

          1 GB per TB is a rule of thumb sizing for enabling dedupe. Don't enable dedupe, its only really useful for fileservers where you are storing multiple copies of the same sort of thing, like backups of different machines.

    3. Jad

      Re: ZFS is for dedicated file-servers

      *cough* software raid boot disk, with almost no hassle *cough*

      Another amazing feature of it on the desktop is the compression out of the box ... The Lz4 compression used has been proven to take less time than not compressing, as the algorithm is so quick ...

      Ddrescue or similar to a file and find out that it only takes up the space of the used data, automatically compressing all the blank space.

    4. Kevin McMurtrie Silver badge

      Re: ZFS is for dedicated file-servers

      It's highly customizable so it can be suited for desktop and server use. You can even create many mount points per pool and give them different options. It's a GUI away from being a filesystem for everyone.

      My only complaint about ZFS is that it's buggy once you leave the happy path. For all those bugs, it still hasn't lost any data. It even survived having 5 SATA cables simultaneously go bad in a raid during a drive swap.

    5. LDS Silver badge

      Re: ZFS is for dedicated file-servers

      ZFS support doesn't mean you have to use it as your primary file system. For example it means you can mount ZFS disks. Just like if Linux would got very good NTFS support, it wouldn't mean you should use it, it would make far easier to access NTFS disks when needed.

      The idea that "Ubuntu is unlikely to be used for those" is wrong too. Is more unlikely to be used as a dedicated file server without ZFS than with it. Anyway, ZFS memory requirements are usually calculated exactly when using it as a dedicated file server with many concurrent users. For single-user use, it does work with far less memory. On secondary storage, some of the features can be appealing to some users.

      Today most solutions are *BSD based, but *BSD is much more picky about the hardware you're using because its hardware support and drivers availability still reminds those of Linux many moons ago. Just read some of those forums, some are horrified and even refuse to help you if you're not running on the anointed hardware. ZFS on Linux does make sense.

      1. Bronek Kozicki Silver badge

        Re: ZFS is for dedicated file-servers

        Hah, this brings me back to memories of trying to install FreeBSD 12.0 in a libvirt VM. None of the modern machine types would work, I had to go back to i440fx with a legacy BIOS boot.

    6. Len Silver badge
      Stop

      Re: ZFS is for dedicated file-servers

      I would say that is nonsense. Every single one of our servers and VMs (even the smallest with just 1 core, 1GB RAM) runs ZFS as their root and data file system.

      Why? Because we like the data security it gives and is the required file system for iocage containers so that settles it.

      As far as I know the RAM hunger is only an issue in dedicated file servers where you want to use advanced deduplication features. For desktop and small server use you just don't use dedup.

      1. matt 83

        Re: ZFS is for dedicated file-servers

        And AFAIK you shouldn't use those dedupe settings unless you really know what you're doing as they aren't suitable for a lot of data sets.

        The whole "ZFS always requires a lot of RAM" is just rubbish.

        The Oracle problem is a much bigger concern than any technical issue.

  2. Andy Non Silver badge
    Happy

    Good to see

    it is still in development in these strange times; though maybe all the developers are just working from home on it anyway.

    Personally I'll wait for the Linux Mint version of it to come along. Looking forward to something a tad different. Still using Mint 18.3 Cinnamon.

    1. CAPS LOCK Silver badge

      "I'll wait for the Linux Mint version" Exactly...

      .... time and again Linux Mint has proved a better option. Additionally, Canonical is getting far too chummy with Microsoft for my liking.

  3. cheb

    It's pronounced foosa BTW. I was fortunate to be involved with tracking them for a research project a few years back.

    1. Steve K Silver badge

      Foosa

      Correct (Foosa) - as evidenced by Sacha Baron-Cohen's character King Julien XIII in Madagascar!

    2. sansva

      I *will* not pronounce it "foosa". If whoever created the spelling for it wanted it pronounced that way, they should have spelled it that way. If the claim is made that that is the way it is pronounced in whatever dialect that is supposed to be, then it isn't English.

      1. fandom

        Are you seriously trying to argue that English spelling and pronunciation is consistent?

      2. Androgynous Cupboard Silver badge

        Well done you. I'm reliably informed that spelling "Fossa" was chosen by St John Menzies-Beauchamp, late of Burpham, Worcestershire, who was well known for choosing the spell a word the way it was pronounced.

        1. Tom 38 Silver badge
          Thumb Up

          Well done - for our American cousins, that name is pronounced "Sin-gin Ming Bow-shomp" of "Burr-fam Wooster-sheer".

          I also like "Happisburgh" in Norfolk, pronounced "Hays-boro".

          1. Androgynous Cupboard Silver badge

            Interesting. I would have gone for "Sin jin Ming-gis Beech-ham of Bur-tham Wooster-sher", which I suppose only helps the point I was making. I used to live near a Beauchamp road in Clapham, was told under no uncertain terms it was "Beech-ham" and staying that way.

            Likewise the "th" sound in Burpham derives from a norse thorn - þ, which became a "p" in our spelling.

            (I wonder how much of our differences are regional? I'm mongrel London area)

            You win on Happisburgh, haven't seen that one. It's on my list.

          2. Anonymous Coward
            Anonymous Coward

            They had a Sin-Jin / St John in Airwolf!

            Oh, and I miss John Menzies...

      3. Anonymous Coward
        Anonymous Coward

        You foll.

  4. Anonymous Coward
    Anonymous Coward

    Nice to hear, but since as you say 95% of installations are the previous LTS version 18.04, wouldn't it make more sense to report on the differences between THAT and 20.04 LTS? Rather than 19.10 and 20.04 LTS, which is going to be a comparatively small percentage of the userbase?

  5. sansva

    I hope you guys will do a proper review of Kubuntu 20.04 as well.

    1. Anonymous Coward
      Anonymous Coward

      Kubuntu will surely be essentially the same regarding the underlying OS features, it just installs KDE as the initial desktop environment, instead of Gnome...?

      A desktop environment isn't an OS, it's just an interface. And the great thing about unix is that you can choose whichever desktop environment you most prefer. And that applies just as much to whatever colour of Ubuntu you started with as it does to any other distro.

      1. ovation1357

        "And the great thing about unix is that you can choose whichever desktop environment you most prefer'

        Which is exactly why I've been running Linux 'on the desktop' for about 13 years. The choice is wonderful.

        Meanwhile, whilst MacOS is okay you're tied to Apple's choice of interface despite some degree of customisation being possible (N.B. If Mac could properly support a secondary copy-paste buffer with highlight to copy, middle click to paste then I just might even be persuaded to use it)

        And Windows, well... What a total cluster fuck of a UI it has now! At least up until Windows 7 there we many ways to customise it to your personal taste. Then Windows 8 onwards with TIFKAM: nada! A terribly, fugly, flat UI which almost zero options to customise anything beyond some largely useless colour and font size options

        If Microsoft is such a big fan of Linux now, maybe they could make Windows 10 KDE edition or, for my preference: Windows 10 MATE edition :-)

    2. The BigYin

      Kubuntu?

      Nah, wait a bit longer for the new Neon to drop and get all the new hotness with the latest KDE.

      1. Degenerate Scumbag

        Re: Kubuntu?

        Indeed, I'm honestly surprised that Kubuntu still exists. What's the point of it now?

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