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ZFS 2.3 released with ZFS raidz expansion

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Re: ZFS 2.3 released with ZFS raidz expansion

#151

Post by zbentley »

endorphine wrote: post #25

Can someone describe why they would use ZFS (or similar) for home usage?

I use ZFS for boot and storage volumes on my main workstation, which is primarily that--a workstation, not a server or NAS. Some benefits:

- Excellent filesystem level backup facility. I can transfer snapshots to a spare drive, or send/receive to a remote (at present a spare computer, but rsync.net looks better every year I have to fix up the spare).

- Unlike other fs-level backup solutions, the flexibility of zvols means I can easily expand or shrink the scope of what's backed up.

- It's incredibly easy to test (and restore) backups. Pointing my to-be-backed-up volume, or my backup volume, to a previous backup snapshot is instant, and provides a complete view of the filesystem at that point in time. No "which files do you want to restore" hassles or any of that, and then I can re-point back to latest and keep stacking backups. Only Time Machine has even approached that level of simplicity in my experience, and I have tried a lot of backup tools. In general, backup tools/workflows that uphold "the test process is the restoration process, so we made the restoration process as easy and reversible as possible" are the best ones.

- Dedup occasionally comes in useful (if e.g. I'm messing around with copies of really large AI training datasets or many terabytes of media file organization work). It's RAM-expensive, yes, but what's often not mentioned is that you can turn it on and off for a volume--if you rewrite data. So if I'm looking ahead to a week of high-volume file wrangling, I can turn dedup on where I need it, start a snapshot-and-immediately-restore of my data (or if it's not that many files, just cp them back and forth), and by the next day or so it'll be ready. Turning it off when I'm done is even simpler. I imagine that the copy cost and unpredictable memory usage mean that this kind of "toggled" approach to dedup isn't that useful for folks driving servers with ZFS, but it's outstanding on a workstation.

- Using ZFSBootMenu outside of my OS means I can be extremely cavalier with my boot volume. Not sure if an experimental kernel upgrade is going to wreck my graphics driver? Take a snapshot and try it! Not sure if a curl | bash invocation from the internet is going to rm -rf /? Take a snapshot and try it! If my boot volume gets ruined, I can roll it back to a snapshot in the bootloader from outside of the OS. For extra paranoia I have a ZFSBootMenu EFI partition on a USB drive if I ever wreck the bootloader as well, but the odds are that if I ever break the system that bad the boot volume is damaged at the block level and can't restore local snapshots. In that case, I'd plug in the USB drive and restore a snapshot from the adjacent data volume, or my backup volume ... all without installing an OS or leaving the bootloader. The benefits of this to mental health are huge; I can tend towards a more "college me" approach to trying random shit from StackOverflow for tweaking my system without having to worry about "adult professional me" being concerned that I don't know what running some random garbage will do to my system. Being able to experiment first, and then learn what's really going on once I find what works, is very relieving and makes tinkering a much less fraught endeavor.

- Being able to per-dataset enable/disable ARC and ZIL means that I can selectively make some actions really fast. My Steam games, for example, are in a high-ARC-bias dataset that starts prewarming (with throttled IO) in the background on boot. Game load times are extremely fast--sometimes at better than single-ext4-SSD levels--and I'm storing all my game installs on spinning rust for $35 (4x 500GB + 2x 32GB cheap SSD for cache)!

Re: ZFS 2.3 released with ZFS raidz expansion

#152

Post by rekoil »

uniqueuid wrote: post #4

It's good to see that they were pretty conservative about the expansion. Not only is expansion completely transparent and resumable, it also maintains redundancy throughout the process. That said, there is one tiny caveat people should be aware of: > After the expansion completes, old blocks remain with their old data-to-parity ratio (e.g. 5-wide RAIDZ2, has 3 data to 2 parity), but distributed among the larger set o…

Yaeh it's a pretty huge caveat to be honest.

    Da1 Db1 Dc1 Pa1 Pb1
    Da2 Db2 Dc2 Pa2 Pb2
    Da3 Db3 Dc3 Pa3 Pb3
    ___ ___ ___ Pa4 Pb4
___ represents free space. After expansion by one disk you would logically expect something like:

    Da1 Db1 Dc1 Da2 Pa1 Pb1
    Db2 Dc2 Da3 Db3 Pa2 Pb2
    Dc3 ___ ___ ___ Pa3 Pb3
    ___ ___ ___ ___ Pa4 Pb4
But as I understand it it would actually expand to:

    Da1 Db1 Dc1 Dd1 Pa1 Pb1
    Da2 Db2 Dc2 Dd2 Pa2 Pb2
    Da3 Db3 Dc3 Dd3 Pa3 Pb3
    ___ ___ ___ ___ Pa4 Pb4
Where the Dd1-3 blocks are just wasted. Meaning by adding a new disk to the array you're only expanding free storage by 25%... So say you have 8TB disks for a total of 24TB of storage free originally, and you have 4TB free before expansion, you would have 5TB free after expansion.

Please tell me I've misunderstood this, because to me it is a pretty useless implementation if I haven't.

Re: ZFS 2.3 released with ZFS raidz expansion

#153

Post by BSDobelix »

bhaney wrote: post #150
BSDobelix wrote: post #149

Earlier quoted context omitted.

Then let me tell you that FreeBSD or OmniOS is what you really want ;)

You're now 0 for 2 at telling me what I want

The customer is not always right, however a good/modern Filesystem really would be something for Linux ;)

Re: ZFS 2.3 released with ZFS raidz expansion

#155

Post by chillfox »

Jnr wrote: post #135
nabla9 wrote: post #124

Earlier quoted context omitted.

License is not a real issue. It must be just distributed in separate module. No big hurdle.

From my point of view it is a real usability issue. zfs modules are not in the official repos. You either have to compile it on each machine or use unofficial repos, which is not exactly ideal and can break things if those repos are not up to date. And I guess it also needs some additional steps for secureboot setup on some distros? I really want to try zfs because btrfs has some issues with RAID5 and RAID6 (it is no…

I have been using ZFS on Mint and Alpine Linux for years for all drives (including root) and have never had an issue. It's been fantastic and is super fast. My linux/zfs laptop loads games much faster than an identical machine running Windows.

I have never had data corruption issues with ZFS, but I have had both xfs and ext4 destroy entire discs.

Re: ZFS 2.3 released with ZFS raidz expansion

#156

Post by GuB-42 »

nabla9 wrote: post #124
GuB-42 wrote: post #73

Earlier quoted context omitted.

To be honest, the situation with Linux is barely better. ZFS has license issues with Linux, preventing full integration, and Btrfs is 15 years in the making and still doesn't match ZFS in features and stability. Most Linux distros still use ext4 by default, which is 19 years old, but ext4 is little more than a series of extensions on top of ext2, which is the same age as NTFS. In all fairness, there are few OS compon…

License is not a real issue. It must be just distributed in separate module. No big hurdle.

It is a problem because most of the internal kernel APIs are GPL-only, which limit the abilities of the ZFS module. It is a common source of argument between the Linux guys and the ZFS on Linux guys.

The reason for this is not just to piss off non-GPL module developers. GPL-only internal APIs are subject to change without notice, even more so than the rest of the kernel. And because the licence may not allow the Linux kernel developers to make the necessary changes to the module when it happens, there is a good chance it breaks without warning.

And even with that, all internal APIs may change, it is just a bit less likely than for the GPL-only ones, and because ZFS on Linux is a separate module, there is no guarantee for it to not break with successive Linux versions, in fact, it is more like a guarantee that it will break.

Linux is proudly monolithic, and as constantly evolving a monolithic kernel, developers need to have control over the entire project. It is also community-driven. Combined, you need rules to have the community work together, or everything will break down, and that's what the GPL is for.

Re: ZFS 2.3 released with ZFS raidz expansion

#157

Post by [deleted] »

crest wrote: post #141
azalemeth wrote: post #96

Earlier quoted context omitted.

My understanding is that single-disk btrfs is good, but raid is decidedly dodgy; https://btrfs.readthedocs.io/en/latest/btrfs-man5.html#raid5... states that: > The RAID56 feature provides striping and parity over several devices, same as the traditional RAID5/6. > There are some implementation and design deficiencies that make it unreliable for some corner cases and *the feature should not be used in production, only…

One problem with your setup is that ZFS by design can't use a traditional *nix filesystem buffer cache. Instead it has to use its own ARC (adaptive replacement cache) with end-to-end checksumming, transparent compression, and copy-on-write semantics. This can lead to annoying performance problems when the two types of file system caches contest for available memory. There is a back pressure mechanism, but it effectiv…

[deleted]

Re: ZFS 2.3 released with ZFS raidz expansion

#159

Post by wjdp »

uniqueuid wrote: post #4

It's good to see that they were pretty conservative about the expansion. Not only is expansion completely transparent and resumable, it also maintains redundancy throughout the process. That said, there is one tiny caveat people should be aware of: > After the expansion completes, old blocks remain with their old data-to-parity ratio (e.g. 5-wide RAIDZ2, has 3 data to 2 parity), but distributed among the larger set o…

Caveat is very much expected, you should expect ZFS features to not rewrite blocks. Changes to settings only apply to new data for example.

Re: ZFS 2.3 released with ZFS raidz expansion

#160

Post by chillfox »

kwanbix wrote: post #64
poisonborz wrote: post #59

I just don't get it how the Windows world - by far the largest PC platform per userbase - still doesn't have any answer to ZFS. Microsoft had WinFS and then ReFS but it's on the backburner and while there is active development (Win11 ships some bits time to time) release is nowhere in sight. There are some lone warriors trying the giant task of creating a ZFS compatibility layer with some projects, but they are far f…

Honest question. As an end user that uses Windows and Linux and does not uses ZFS, what I am missing?

Much faster launch of applications/files you use regularly. Ability to always rollback updates in seconds if they cause issues thanks to snapshots. Fast backups with snapshots + zfs send/receive to a remote machine. Compressed disks, this both let's you store more on a drive and makes accessing files faster. Easy encryption. ability to mirror 2 large usb disks so you never have your data corrupted or lose it from drive failures. Can move your data or entire os install to a new computer easily by using a live disk and just doing a send/receive to the new pc.

(I have never used dedup, but it's there if you want I guess)

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