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The State of ZFS on Linux

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Re: The State of ZFS on Linux

#81

Post by DiabloD3 »

fsckin wrote: post #78
seoguru wrote: post #75

I have a laptop running ubuntu with a single SSD. Does it make sense to run it with ZFS to get compression and snapshots? If I add a hard drive, again does it make sense (perhaps using SSD as cache (arc?) )

I've never heard of someone using ZFS with a single disk. You're probably better off with ext4. The compression and deduplication features of ZFS is terrific on network filers. Compression could possibly improve performance slightly on a single disk system. With two disks, I'd say you'd probably be better off with running RAID0 (or no RAID at all) and having a great backup plan. Using another SSD to cache writes to a…

Honestly, I recommend XFS over ext4. It seems to be a much more mature file system, and Redhat-family distros (RHEL, Centos, Scientific, etc) have switched to XFS as the default filesystem (instead of moving to ext4 from 6.x's default of ext3; 6.x does not support XFS or ext4 for root).

XFS performs better out of the box on a wide range of hardware, while seemingly giving stronger data reliability guarantees (but not anywhere near ZFS's).

ZFS on a single disk, however, will still give you data checksumming, so you can detect silent data corruption. XFS's sole missing feature as a basic filesystem, imo, is data checksumming.

Re: The State of ZFS on Linux

#82

Post by mbreese »

justizin wrote: post #72
mbreese wrote: post #71

Earlier quoted context omitted.

The previous poster is well aware of what ZFS on Linux is. Licensing matters. It may not matter in terms of what I can do with my servers. I can compile ZFS and run it just fine on Linux. But you won't find Red Hat doing it. You won't find IBM doing it. Linus won't be adding it into the mainline tree anytime soon. This means that there may be "technical" solutions to getting ZFS running on Linux, but that also means…

Right, but had you read the discussion this thread is about, you can see that Debian is working on a roadmap that includes binary drivers, shipped with the OS, available during the install. Linus has traditionally done a poor job of ensuring that filesystems will work well in production, ext4 being a _fantastic_ example of that. I appreciate the work he does, but I don't quite give a fuck if he is scanning the source…

Debian is working on a roadmap that includes shipping source drivers to be slipstreamed in as dynamic modules.

DKMS is a tool, but it's hardly the same as a good, in tree module. I remember having tons of issues with DKMS WiFi drivers back when I still ran a Linux laptop (10-ish years ago). If you get an upstream kernel upgrade and the ZFS DKMS module doesn't compile against it, you're screwed. Can you imagine trying to debug DKMS issues with your main filesystem? I hope you leave an ext2/3/4 volume around for booting and root.

I'm glad that you feel like you can discount the work that IBM and Red Hat have done to advance Linux, but they've done a ton to make sure that Linux could take over data centers.

Good to know... Thanks!

Re: The State of ZFS on Linux

#83

Post by ScottBurson »

ryao wrote: post #57
foobarqux wrote: post #33

Earlier quoted context omitted.

Can you speak more about why ZFS is better than BTRFS?

A btrfs versus ZFS comparison probably deserves a blog post of its own, but I will try to address your question. I wrote the following on this topic last year: https://groups.google.com/d/msg/funtoo-dev/g9OY_vqVpCM/VTKF8... However, significant time has passed and it requires some corrections to be current: 1. I have not heard of any recent data corruption issues in btrfs, although I have not looked into them lately.…

I got the impression somewhere that btrfs RAID 5/6 support allows, or will allow, new devices to be added to an existing RAID group.

That's an important feature for home and small business users. Having to replace every drive in a RAID group to grow it, as ZFS requires, is painful and expensive.

Fortunately, drives are cheap enough these days that you can just way oversize your pool to begin with. But anyone switching to ZFS should be aware of the need to do this.

Re: The State of ZFS on Linux

#84

Post by walterbell »

DiabloD3 wrote: post #40
ryao wrote: post #35

Earlier quoted context omitted.

Debian is the last major Linux distribution where it is not easy to do / on ZFS. It might be possible to implement a module for Debian's initramfs generator in ZoL upstream. I suggest filing an issue to inquire about this possibility: https://github.com/zfsonlinux/zfs/issues/new

They have it for Ubuntu, but Ubuntu and Debian have somewhat diverged on how it is done. It is not a big issue for me on this build, but if I wanted to do large scale file servers and didn't want to stash a USB dongle in the box for root, it would be useful. Although, I guess I could use FreeBSD if I didn't need KVM and/or Xen....

How about FreeBSD guest on Xen with Linux dom0?

https://wiki.freebsd.org/FreeBSD/Xen

Re: The State of ZFS on Linux

#85

Post by click170 »

rodgerd wrote: post #64
DiabloD3 wrote: post #25

I've used ZoL since it was created, and zfs-fuse before that. I ran it on my workstation for a few years (managing a 4x750gb RAID-Z (= ZFS's RAID-5 impl), with ext3 on mdadm RAID 1 2x400gb root), and then swapped to BTRFS for 2x2TB BTRFS native RAID 1 (which was Oracle's ZFS competitor that seems to be largely abandoned although I see commits in the kernel changelog periodically), and now back to ZFS on a dedicated f…

> (which was Oracle's ZFS competitor that seems to be largely abandoned although I see commits in the kernel changelog periodically) Under heavy development, officially supported by most of the major commercial distros, and still designated by Linus as the ext* replacement as the standard Linux filesystem.

I'm curious where the idea that it's largely abandoned comes from. This isn't the first time I've heard it, but each time I've heard it and looked, the project looks far from dead or abandoned.

Re: The State of ZFS on Linux

#86

Post by curiousbiped »

seoguru wrote: post #75

I have a laptop running ubuntu with a single SSD. Does it make sense to run it with ZFS to get compression and snapshots? If I add a hard drive, again does it make sense (perhaps using SSD as cache (arc?) )

Well, with ZFS you could squirt snapshots of /home to another box for backups. Since they're just the changed blocks, they'd be fairly small.

Re: The State of ZFS on Linux

#87

Post by lmz »

DiabloD3 wrote: post #81
fsckin wrote: post #78

Earlier quoted context omitted.

I've never heard of someone using ZFS with a single disk. You're probably better off with ext4. The compression and deduplication features of ZFS is terrific on network filers. Compression could possibly improve performance slightly on a single disk system. With two disks, I'd say you'd probably be better off with running RAID0 (or no RAID at all) and having a great backup plan. Using another SSD to cache writes to a…

Honestly, I recommend XFS over ext4. It seems to be a much more mature file system, and Redhat-family distros (RHEL, Centos, Scientific, etc) have switched to XFS as the default filesystem (instead of moving to ext4 from 6.x's default of ext3; 6.x does not support XFS or ext4 for root). XFS performs better out of the box on a wide range of hardware, while seemingly giving stronger data reliability guarantees (but not…

RHEL6 uses ext4 as default[1] filesystem. It certainly does support ext4 as root.

[1]: https://access.redhat.com/documentation/en-US/Red_Hat_Enterp...

Re: The State of ZFS on Linux

#89

Post by voltagex_ »

ryao wrote: post #52
nisa wrote: post #47

Earlier quoted context omitted.

I'm not the op but I'm running ZoL on a small cluster with 200 HDDs and 50 machines. I've also tested btrfs. Why is ZFS better (IMHO): + Tooling. The zpool and zfs commands are clear, easy to use and well documented. btrfs e.g. has no way to get a list of files with checksum problems. Also automounting and setting flexible mount points as well as the whole zfs get/set concept felt like a really concise way to configu…

Below are a few remarks: To expand on your LZ4 comment, LZ4 is 3 times faster than LZO at decompression: https://code.google.com/p/lz4/ However, LZ4's real innovation is on incompressible data. I do not have a reference at the moment, but there have been benchmarks on the userland lz4 tool on incompressible data that show it processing 10GB/sec. This is because LZ4 uses a hash table that enables it to give up when tr…

Is it possible to integrate the ZoL modules with DKMS so that kernel upgrades are handled automagically?

Re: The State of ZFS on Linux

#90

Post by voltagex_ »

ScottBurson wrote: post #83
ryao wrote: post #57

Earlier quoted context omitted.

A btrfs versus ZFS comparison probably deserves a blog post of its own, but I will try to address your question. I wrote the following on this topic last year: https://groups.google.com/d/msg/funtoo-dev/g9OY_vqVpCM/VTKF8... However, significant time has passed and it requires some corrections to be current: 1. I have not heard of any recent data corruption issues in btrfs, although I have not looked into them lately.…

I got the impression somewhere that btrfs RAID 5/6 support allows, or will allow, new devices to be added to an existing RAID group. That's an important feature for home and small business users. Having to replace every drive in a RAID group to grow it, as ZFS requires, is painful and expensive. Fortunately, drives are cheap enough these days that you can just way oversize your pool to begin with. But anyone switchin…

Can you link to anything about oversizing the pool? I think I vaguely remember a trick with creating a sparse file and adding that to the pool until you can replace that with a drive.
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