ZFS On Linux With Ubuntu 12.04 LTS

[johnc]

It'd be good to see a redone set of benchmarks for a properly tuned ZFS setup - and bear in mind that ZFS isn't just a "filesystem" - it's a complete storage environment which replaces RAID+Partitions+LVM+filesystem and is intended for multi-Tb scale installations (I run 12Tb at home on 5400RPM drives, and several hundred Tb at work...)

Do you use Linux or another OS?

I want to build a home file server eventually and am still undecided on OS choice.

[linux5850]

From some of the comments above by some of the developers then does it mean that ZFS is not a good choice for a root file system on a laptop? Sounds like only good for multi-disk multi-TB environments. Though it has features which would be very useful for desktop/laptop environments.

Has the bug of not being able to use preemption been fixed?

[ryao]

Isn't it good that all code in the Linux kernel is covered by a single license instead of a plethora license?
I think it is great that all code in the Linux kernel is covered by just one single license.

If ZFS was under the BSD or ISC license, then it could be incorporated into the Linux kernel.

Not all of the code in Linux is covered by a single license. The graphics drivers are either MIT licensed or X11 licensed. That is how OpenBSD is able to port them without conflicting with their strict licensing requirements. Also, the TCP/IP stack was never licensed under the GPL. It was borrowed/copied/stolen/<insert participle> from BSD.

I suggest that you spend some time reading the kernel source code firsthand. You should find it to be an enlightening experience.

From some of the comments above by some of the developers then does it mean that ZFS is not a good choice for a root file system on a laptop? Sounds like only good for multi-disk multi-TB environments. Though it has features which would be very useful for desktop/laptop environments.

Has the bug of not being able to use preemption been fixed?

There is currently an issue with suspend/resume that might be related to Gentoo Hardened (no one has tested it without hardening), but aside from that, it works fine. I use it on a desktop and I know two people who use it on laptops.

As for preemption, there are patches available that makes it work. They are available in the following pull requests:

https://github.com/zfsonlinux/spl/pull/98
https://github.com/zfsonlinux/zfs/pull/674

The patches work well on my desktop, but preemption does not yield much qualitative benefit on my system. ZFS' ARC algorithm improves my desktop's interactive response far more than preemption does.

Also, you can use voluntary preemption without those patches. Voluntary preemption was implemented after full preemption with the claim that it was even better for low latency audio, although you can be the judge of that.

[Stellarwind]

Do you use Linux or another OS?
I want to build a home file server eventually and am still undecided on OS choice.

Here is a linux+zfs homeserver story: https://mocko.org.uk/b/2012/06/17/ho...croserver-joy/
FreeBSD zfs is a good choice for server as well.
Solaris/Illumos has device support issues

[smitty3268]

From some of the comments above by some of the developers then does it mean that ZFS is not a good choice for a root file system on a laptop? Sounds like only good for multi-disk multi-TB environments. Though it has features which would be very useful for desktop/laptop environments.

Has the bug of not being able to use preemption been fixed?

I think it's more accurate to say it's overengineered for a laptop environment like you are describing. It was designed primarily for Unix mainframes, and the fact that it can scale down to laptops is a nice feature, not a core requirement.

A simpler FS like Ext4 will likely be better in your case, unless you actually want to take advantage of some of the features that ZFS provides - in that case, i'd say you could certainly go for it if you want to.

[linux5850]

I think it's more accurate to say it's overengineered for a laptop environment like you are describing. It was designed primarily for Unix mainframes, and the fact that it can scale down to laptops is a nice feature, not a core requirement.

A simpler FS like Ext4 will likely be better in your case, unless you actually want to take advantage of some of the features that ZFS provides - in that case, i'd say you could certainly go for it if you want to.

I disagree. Used EXT4 in the past and it bad for multitasking desktop/laptop environment with heavy compiling in the background and when your system crashes you lose many files. I wanted to use ZFS for the features and the speed (once you tune it for the system you're using).

[smitty3268]

I disagree. Used EXT4 in the past and it bad for multitasking desktop/laptop environment with heavy compiling in the background and when your system crashes you lose many files. I wanted to use ZFS for the features and the speed (once you tune it for the system you're using).

As I said, if you actually intend to use the features then go ahead, it makes sense to use ZFS for that reason.

But expect it to be slower on your hardware for your uses. Where ZFS speed shines is when you are dealing with multiple high speed disks, not a single laptop disk that is undergoing heavy writes from compiling.

[disi]

The best feature of zfs on a desktop or laptop is the volume management. Usually the disks/ssds are quiet small in a laptop and you do not want to waste disk space with partitioning, so with zfs you can just create one vdev and have snapshots of most of the configs/documents and can use compression for home folders. My ratio is like 1.34 on the home folder with documents... what is there not useful on a laptop?

[linux5850]

As I said, if you actually intend to use the features then go ahead, it makes sense to use ZFS for that reason.

But expect it to be slower on your hardware for your uses. Where ZFS speed shines is when you are dealing with multiple high speed disks, not a single laptop disk that is undergoing heavy writes from compiling.

That's the thing. Would it be slower than BTRFS? That's one of the reasons non-enterprise users want to see how ZFS performance compares to BTRFS and other filesystems.

[johnc]

Perhaps it was then, perhaps not now.

Oracle's largest installed base is on Linux, not Solaris. They know what side their bread is buttered on.

The problem with the code being released under CDDL is that it may be difficult for Oracle to now change the licensing, depending how any 3rd party copyright assignments were made (the same issue with so many contributors to the linux kernel and GPL)

Well it looks like Oracle has chosen to close-source their newer Solaris versions and ZFS updates.

So I guess what was released from Sun is all we have to work with, and the subsequent updates made under the OpenIndiana project (which is probably going to have more momentum).

But as long as we can have a ZFS kernel module like we can have video drivers, it's not too big of a deal. The end-user just has to install it himself.