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ZFS fans, rejoice – RAIDz expansion will be a thing soon

arstechnica.com

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Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#71

Post by nix23 »

imiric wrote: post #69
nix23 wrote: post #65

Earlier quoted context omitted.

> LUKS+LVM+SnapRAID + your fs Yeah that sounds like a lot less complexity

ZFS has all of these features and more. If I don't need those extra features by definition it's a less complex system. Using composable tools is also better from a maintenance standpoint. If tomorrow SnapRAID stops working, I can replace just that component with something else without affecting the rest of the system.

Since all those tools are from different dev's the system gets more complex. But hey if you really think that ZFS is to complex to hold 55 petabytes because it has to many potential bugs you should tell them:

https://computing.llnl.gov/projects/zfs-lustre

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#72

Post by benlivengood »

Dylan16807 wrote: post #31
d33lio wrote: post #2

I'll believe it when I see it, why anyone uses BTRFs (UnRaid or any other form of software raid that isn't ZFS) is still beyond me. At least when we're not talking SSD's ;) ZFS is incredible, curious to mess around with these new features!

> why anyone uses BTRFs (UnRaid or any other form of software raid that isn't ZFS) is still beyond me. BTRFS can do after-the-fact deduplication (with much better performance than ZFS dedup) and copy-on-write files. And you can turn snapshots into editable file systems.

I think cloning a zfs snapshot into a writeable filesystem matches at least the functionality of btrfs writeable snapshots, but I could be ignorant about some use-cases.

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#73

Post by the8472 »

nix23 wrote: post #63
the8472 wrote: post #32

Earlier quoted context omitted.

btrfs does have some advantages over zfs - no data duplicated between page cache and arc - no upgrade problems on rolling distros - balance allows restructuring the array - offline dedup, no need for huge dedup tables - ability to turn off checksumming for specific files - O_DIRECT support - reflink copy - fiemap - easy to resize

But the main thing of an fs is to preserve your files...btrfs can't even check the most important point.

The checksumming helps to spot faulty hardware, that's a step above most other filesystems and often smart info too.

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#74

Post by usefulcat »

nimbius wrote: post #53

this might sound like a troll comment but its coming from someone with almost zero experience with raid. What is the purpose of ZFS in 2021 if we have hardware RAID and linux software RAID? BTRFS does RAID too. Why would people choose ZFS in 2021 if both Oracle and Open Source users have 2 competing ZFS? are they interoperable?

The last time I had to use HW raid it was horrible. The software for managing the RAID array was a poorly documented, difficult to use proprietary blob. I used it for years and the experience never improved. And this is a thing where if you make a mistake you can destroy the very data that you've gone to such lengths to protect. Having switched to ZFS several years ago, I lack to the words to express how much I don't miss having to deal with that.

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#75

Post by mixedCase »

nix23 wrote: post #67
mixedCase wrote: post #57

Earlier quoted context omitted.

I just put two 8TB drives into btrfs because it's a home server, I can't provision things up front. One day I may put a third 8TB drive and turn this RAID1 into RAID5. btrfs lets me do that, zfs doesn't, simple as. One day I may switch the whole thing to bcachefs, which I've donated and am looking forwards to. For the moment, btrfs will have to do. EDIT: downvoted by... the filesystem brigade?

>RAID5 I wish you lots of fun with that on btrfs :) Edit: https://btrfs.wiki.kernel.org/index.php/Status RAID56 Unstable n/a write hole still exists > treated as if I'm storing business data or precious memories without backups, guess I'm just dumb No your not, but don't use unstable features in a filesystem

Well, that's the idea! This a low I/O media server where all the important stuff (The whole point of me using RAID1 (and maybe later RAID5) is that if a disk goes bust, odds are I can still watch a movie from it until I can get another disk. What's more, if I ever fill the RAID1 and I don't feel like breaking the piggy bank for another disk, I can go JBOD as far as my usecase is concerned.

But hey, if the orange website tells me all servers are supposed to be treated as if I'm storing business data or precious memories without backups, guess I'm just dumb. On that note: donations welcome, each 8TB disk costs close to 500 USD here in Uruguay, so if anyone's first world opinion can buy me a couple so I can use the Right Filesystem™, I'd appreciate it!

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#76

Post by garmaine »

nickik wrote: post #60
nimbius wrote: post #53

this might sound like a troll comment but its coming from someone with almost zero experience with raid. What is the purpose of ZFS in 2021 if we have hardware RAID and linux software RAID? BTRFS does RAID too. Why would people choose ZFS in 2021 if both Oracle and Open Source users have 2 competing ZFS? are they interoperable?

> What is the purpose of ZFS in 2021 if we have hardware RAID Hardware RAID is actually older then ZFS style software RAID. ZFS was specifically designed fix the issues with hardware RAID. The problem with Hardware RAID is that is has no ideas what going on on top of it, and even worse, its a mostly a bunch of closed-source fireware from a vendor. And they cost money. You can find lots of terrible story about those.…

He was referring to mdadm RAID.

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#77

Post by imiric »

nix23 wrote: post #71
imiric wrote: post #69

Earlier quoted context omitted.

ZFS has all of these features and more. If I don't need those extra features by definition it's a less complex system. Using composable tools is also better from a maintenance standpoint. If tomorrow SnapRAID stops working, I can replace just that component with something else without affecting the rest of the system.

Since all those tools are from different dev's the system gets more complex. But hey if you really think that ZFS is to complex to hold 55 petabytes because it has to many potential bugs you should tell them: https://computing.llnl.gov/projects/zfs-lustre

Thankfully I don't have to manage 55 petabytes of data, but good luck to them.

Did you miss the part where I mentioned "for personal use"?

> Since all those tools are from different dev's the system gets more complex.

I fail to see the connection there. Whether software is developed by a single entity or multiple developers has no relation to how complex the end user system will be.

But many small tools focused on just the functionality I need allows me to build a simpler system overall.

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#78

Post by rektide »

nimbius wrote: post #53

this might sound like a troll comment but its coming from someone with almost zero experience with raid. What is the purpose of ZFS in 2021 if we have hardware RAID and linux software RAID? BTRFS does RAID too. Why would people choose ZFS in 2021 if both Oracle and Open Source users have 2 competing ZFS? are they interoperable?

No matter what happens, people will seemingly forever declare BTRFS is not as stable and not as safe. There's a status page that details what BTRFS thinks of itself[1], and I doubt any of the many people docking BTRFS have read or know or care what that page says. There is one issue still being worked out to completion, a "write hole" problem, involving two separate failures, an unplanned/power-loss shut-down, followed by a second disk failure, which can result in some data being lost[2] in RAID5/6 scenarios.

Other than that one extreme double-failure scenario being worked out, BTRFS has proven remarkably stable for a while now. A decade ago that wasn't quite as absolutely bulletproof, but today the situation is much different. Personally, it feels to me like there is a persistent & vocal small group of people who seemingly either have some agenda that makes them not wish to consider BTRFS, or they are unwilling to review & reconsider how things might have changed in the last decade. Not to belabor the point but it's quite frustrating, and it feels a bit odd that BTRFS is such a persistent target of slander & assault. Few other file systems seem to face anywhere near as much criticism, never so out of hand/casually, and honestly, in the end, it just seems like there's some continent of ZFS folks with some strange need to make themselves feel better by putting others down.

One big sign of trust: Fedora 35 Cloud looks likely to switch to BTRFS as default[3], following Fedora 33 desktop lat year making the move. A number of big names use BTRFS, including Facebook. I have yet to see any hyperscalers interested in ZFS.

I'm excited to see ZFS start to get some competent expandability. Expanding ZFS used to be a nightmare. I'll continue running BTRFS for now, but I'm excited to see file systems flourish. Things I wouldn't do? Hardware RAID. Controllers are persnickety weird devices, each with their own invisible sets of constraints & specific firmware issues. If at all possible, I'd prefer the kernel figure out how to make effective use out of multiple disks. BTRFS, and now it seems ZFS perhaps too, do a magical job of making that easy, effective, & fast, in a safe way.

Edit: the current widely-adopted write hole fix is to use RAID1 or RAID1c3 or RAID1c4 (3 copy RAID1, 4 copy RAID1) for meta-data, RAID5/6 for data.

[1] https://btrfs.wiki.kernel.org/index.php/Status

[2] https://btrfs.wiki.kernel.org/index.php/RAID56

[3] https://www.phoronix.com/scan.php?page=news_item&px=Fedora-C...

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#79

Post by garmaine »

milofeynman wrote: post #43

My resizing consists of buying 8 more hard drives that are 2x the previous 8 and moving data over every few years (:

FYI you don’t have to move data. You can just replace each disk one at a time, and after the last replacement you magically have a bigger vpool.

Re: ZFS fans, rejoice – RAIDz expansion will be a thing soon

#80

Post by magicalhippo »

nimbius wrote: post #53

this might sound like a troll comment but its coming from someone with almost zero experience with raid. What is the purpose of ZFS in 2021 if we have hardware RAID and linux software RAID? BTRFS does RAID too. Why would people choose ZFS in 2021 if both Oracle and Open Source users have 2 competing ZFS? are they interoperable?

> What is the purpose of ZFS in 2021 if we have hardware RAID and linux software RAID?

Others have touched on the main points, I just wanted to stress that an important distinction between ZFS and hardware RAID and linux software RAID (by which I assume you mean MD) is that the latter two present themselves as block devices. One has to put a file system on top to make use of them.

In contrast, ZFS does away with this traditional split, and provides a filesystem as well as support for a virtual block device. By unifying the full stack from the filesystem down to the actual devices, it can be smarter and more resilient.

The first few minutes of this[1] presentation does a good job of explaining why ZFS was built this way and how it improves on the traditional RAID solutions.

[1]: https://www.youtube.com/watch?v=MsY-BafQgj4

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