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Linus: Don't Use ZFS

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Re: Linus: Don't Use ZFS

#411

Post by labawi »

bleuarff wrote: post #396
XelNika wrote: post #361

Earlier quoted context omitted.

> Keep in mind that RAID5 isn’t feasible with multi-TB disks (the probability of failed blocks when rebuilding the array is far too high). What makes you say that? I've seen plenty of people make this claim based on URE rates, but I've also not seen any evidence that it is a real problem for a 3-4 drive setup. Modern drives are specced at 1 URE per 10^15 bits read (or better), so less than 1 URE in 125 TB read. Even…

Last time I checked (a few years ago I must say), a 10^15 URE was only for enteprise-grade drives and not for consumer-level, where most drives have a 10^14 URE. Which means your build is almost guaranteed to fail on a large-ish raid setup. So yeah, RAID is still feasible with multi-TB disks if you have the money to buy disks with the appropriate reliability. For the common folk, raid is effectively dead with today's…

Theoretically, if you have a good RAID5, without serious wire-hole and similar issues, then it is strictly better than no RAID and worse than RAID5 and RAID1.

* All localized error are correctable, unless they overlap on different disks, or result in drive ejection. This precisely fixes UREs of non-raid drives.

* If a complete drive fails, then you have a chance of losing some data from the UREs / localized errors. This is approximately the same as if you used no RAID.

As for URE incidence rate - people use multi-TB drives without RAID, yet data loss does not seem prevalent. I'd say it depends .. a lot.

If you use a crappy RAID5, that ejects a drive on a drive partial/transient/read failure, then yes, it's bad, even worse than no RAID.

That being said, I have no idea whether a good RAID5 implementation is available, one that is well interfaced or integrated into filesystem.

Re: Linus: Don't Use ZFS

#412

Post by toyg »

morning_gelato wrote: post #337
ilikejam wrote: post #290

Earlier quoted context omitted.

There were genuine reasons for the CDDL - it wasn't an anti-gpl thing. https://www.youtube.com/watch?v=-zRN7XLCRhc&feature=youtu.be...

Danese Cooper, one of the people at Sun who helped create the CDDL, responded in the comment section of that very video: Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. That was one of the design points of the CDDL. I was in that room, Bryan and you were not, but I know its fun to re-write history to suit your current politics. I pleaded with Sun to use a BSD family license o…

Yeah, it's hard to understand this without context. Sun saw D-Trace and ZFS as the differentiators of Solaris from Linux, a massive competitive advantage that they simply could not (and would not) relinquish. Opensourcing was a tactical move, they were not going to give away their crown jewels with it.

The whole open-source steer by SUN was a very disingenous strategy, forced by the changed landscape in order to try and salvage some parvence of relevance. Most people saw right through it, which is why SUN ended up as it did shortly thereafter: broke, acquired, and dismantled.

Re: Linus: Don't Use ZFS

#413

Post by eitland »

llcoolv wrote: post #404
eitland wrote: post #282

Earlier quoted context omitted.

If anyone thinks this is hyperbole : I worked for a tiny startup (>2 devs full time) where Oracle tried to extract money from us because we used MariaDB on AWS. If you think this sounds ridiculous you probably got it right. (Why? Because someone inexperienced with Oracle had filled out the form while downloading the mySQL client.)

Well... Serves you about right for choosing MySQL over PostgreSQL :)

In my defense it wasn't my choice ;-)

Re: Linus: Don't Use ZFS

#414

Post by barkingcat »

t0astbread wrote: post #331
barkingcat wrote: post #280

Linus is correct in his arguments. As the lead for the linux project, he shouldn't merge things that he feels isn't up to stuff from a license point of view. That's why we have different software. If you asked Theo to merge an encryption algorithm for example into OpenSSH and OpenBSD - he's going to have an opinion about it - and that's his thing. Why would this be controversial at all?

Because people like ZFS and Linux so they want to combine the two.

Then they can go ahead and combine the two! ZFS on linux has a whole team of maintainers.

Linus can do what he wants in regards to his branch (which because he's the lead, becomes official Linux), but there's no reason any one else (or any distro) can't do the integration. That's how open source works!

Of course, whoever does the integration may incur Oracle's wrath. Tread at your own discretion. If those people like it so much that they will put up their own money when Oracle's lawyers come calling, that's completely up to them.

In my opinion, people who constantly clamour for such things against the technical judgment of open source maintainers are freeloaders. They can propose ideas, but just because the maintainer doesn't want to do it doesn't mean they can scream bloody murder. Just put up your own money and fork it and/or maintain your own fork, which is exactly what the ZFS on linux community is doing - which is the right thing.

Anyone else can work with the ZFS on linux maintainers to take a bit of the burden on, whether it's rebasing or updating docs on how the integration works, etc. It's a group effort.

Re: Linus: Don't Use ZFS

#415

Post by _emacsomancer_ »

celticmusic wrote: post #177
gh123man wrote: post #77

Earlier quoted context omitted.

I am also not an expert in this space - but if I understand correctly the reason the linux Nvidia driver sucks so much is that it is not GPL'd (or open source at all). There is little incentive for Nvidia to maintain a linux specific driver, but because it is closed source the community cannot improve/fix it. > Why are all drivers expected to use the GPL? I think the answer to this is: drivers are expect to use the G…

My experience is that linux nvidia drivers are better than the competitors open source drivers.

This was true until relatively recently, but no longer.

Re: Linus: Don't Use ZFS

#416

Post by vetinari »

josefx wrote: post #362
zamalek wrote: post #310

Earlier quoted context omitted.

> ZFS has a CDDL license Java is GPLv2+CPE. That didn't stop Oracle because, as Linus pointed out in the email, Oracle regards their APIs as a separate entity to their code.

Googles Java implementation wasn't GPL licensed, so neither its implementation nor its interface could have been covered by the OpenJDK being GPLv2. I think RMS wouldn't sit by idly either if someone took GCC and forked it under the Apache license.

But Google didn't fork the OpenJDK; they forked Apache Harmony, which was already Apache-licensed.

So it's not comparable with GCC; but comparable to forking clang and keeping clang license. I doubt RMS could be able to say anything.

Re: Linus: Don't Use ZFS

#417

Post by vetinari »

wheybags wrote: post #373
mschuster91 wrote: post #345

Earlier quoted context omitted.

why would you want to embed raid5/6 in the filesystem layer? Linux has battle-tested mdraid for this, I'm not going to trust a new filesystem's own implementation over it. Same for encryption, there are already existing crypto layers both on the block and filesystem (as an overlay) level.

Because the FS can be deeply integrated with the RAID implementation. With a normal RAID, if the data at some address is different between the two disks, there's no way for the fs to tell which is correct, because the RAID code essentially just picks one, it can't even see the other. With ZFS for example, there is a checksum stored with the data, so when you read, zfs will check the data on both and pick the correct…

> With a normal RAID, if the data at some address is different between the two disks, there's no way for the fs to tell which is correct, because the RAID code essentially just picks one, it can't even see the other.

That's problem only with RAID1, only when copies=2 (granted, most often used case) and only when the underlying device cannot report which sector has gone bad.

Re: Linus: Don't Use ZFS

#418

Post by notacoward »

morning_gelato wrote: post #337
ilikejam wrote: post #290

Earlier quoted context omitted.

There were genuine reasons for the CDDL - it wasn't an anti-gpl thing. https://www.youtube.com/watch?v=-zRN7XLCRhc&feature=youtu.be...

Danese Cooper, one of the people at Sun who helped create the CDDL, responded in the comment section of that very video: Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. That was one of the design points of the CDDL. I was in that room, Bryan and you were not, but I know its fun to re-write history to suit your current politics. I pleaded with Sun to use a BSD family license o…

This needs to be more widely known. Sun was never as open or innovative as its engineer/advertisers claim, and the revisionism is irksome. I saw what they had copied from earlier competitors like Apollo and then claimed as their own ideas. I saw the protocol fingerprinting their clients used to make non-Sun servers appear slower than they really were. They did some really good things, and they did some really awful things, but to hear proponents talk it was all sunshine and roses except for a few misguided execs. Nope. It was all up and down the organization.

Re: Linus: Don't Use ZFS

#419

Post by vetinari »

kalleboo wrote: post #267
disordinary wrote: post #202

Earlier quoted context omitted.

There's differing opinions of BTRFS's suitability in production - it's the default filesystem of SUSE on one hand, on the other RedHat has deprecated BTRFS support because they see it as not being production ready and they don't see it being production ready in the near future. They also feel that the more legacy linux filesystems have added features to compete.

It's also the default file system of millions of Synology NASes running in consumer hands (although Synology shimmed on their own RAID5/6 support)

Synology uses standard linux md (for btrfs too). Even SHR (Synology Hybrid RAID) is just different partitions on the drive allocated to different volumes, so you can use mixed-capacity drives effectively.

Re: Linus: Don't Use ZFS

#420

Post by vetinari »

cerved wrote: post #340
quantummkv wrote: post #312

Earlier quoted context omitted.

> There are no (stable) alternatives. BTRFS certainly not, as it's "under heavy development"¹ (since... forever). Unless you are living in 2012 on a RHEL/CENTOS 6/7 machine, btrfs has been stable for way too long. I have been using btrfs as the sole filesystem on my laptop in standard mode, on my desktop as RAID0 and my NAS as RAID1 for more that two years. I have experienced absolutely zero data loss. Infact, btrfs…

I believe he's referring to the raid 5/6 issues

RAID 5/6 issue is the write hole, which is common to all software RAID 5/6 implementations. If it is a problem for you, use either BBU or UPS.

RAIZ/Z2 avoids the issue by having slightly different semantics. That's why it is Z/Z2, not 5/6.

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