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Comment by wireprotocol | Hacker News Reader

Why doesn't Oracle just change ZFS to dual-license GPL/CDDL, and scrap btrfs?

My experiences with ZFS have been quite good, and with btrfs quite bad.

Because Oracle wants you to buy Solaris if you do serious business.

Oracle wants you to buy support contracts. They'd be perfectly happy to have those be for Oracle Linux rather than Solaris since they don't have to do all of the engineering that way.

or Oracle Linux. I don't know if they are shipping ZFS support with it yet. But they are already shipping dtrace with it which suffers from the same license issues.

I asked the Oracle representative at LinuxCon North America 2014 this question and explicitly mentioned that it was already shipping CDDL kernel code because of DTrace. He could not answer this question, but claimed that he would get back to me. So far, I have not heard back.

They are currently using a trick trying to circumvent the EXPORT_SYMBOL_GPL issue. But it is highly dubious whether this is legally sound:

ktime_t dtrace_gethrtime(void) { return ktime_get(); } EXPORT_SYMBOL(dtrace_gethrtime);

http://mjg59.dreamwidth.org/31357.html

In the end I assume this is intentional to keep the license issue of dtrace and ZFS in a dubious state. Thus preventing other distributions from shipping it. Meanwhile Oracle can ship it because they aren't going to sue themselves and the kernel folks seem rather uninterested in lawsuits as well (and even if they did then Oracle could drag it out forever considering that the company seems to have more lawyers than developers).

I guess the question remains, why do they keep developing btrfs ? (do they?)

They had the principal btrfs developer a few years back, but he's currently at Facebook, where they're apparently migrating to btrfs.

Sun received dozens if not hundreds of patents for techniques used in ZFS and since Oracle purchased Sun, it now has those patents. btrfs uses many of the ideas that ZFS uses, so it is highly unlikely that btrfs does not infringe on at least some of those patents. People who use ZFS have a patent grant through the CDDL, but people who use btrfs have no such protection from the GPLv2.

So far, I am not aware of anyone who has gotten any legally binding assurance from Oracle that shipping btrfs will not be a problem. I am also not aware of anyone in the btrfs community asking Oracle to do something about it. If btrfs takes off, the ZFS patent portofilo could ensure that Oracle is the only company that can legally distribute btrfs. Consequently, Oracle's legal department would likely be able to have a field day with any company distributing btrfs. In the meantime, their competition will have to develop workarounds and Oracle would be ahead because they will have a better filesystem than they would have had they been upfront about this issue.

What Oracle might or might not do with the ZFS patent portfolio in the future is speculation, but the fact is that Oracle appears to have reserved the option to use it in future lawsuits.

> What Oracle might or might not do with the ZFS patent portfolio in the future is speculation,

This whole post blows straight through "speculation" and into "unpaid marketing for Oracle" in the worst possible way.

I don't think that's fair at all.

I don't like Oracle, I think they're one of the most evil companies in existence. But that doesn't automatically make anyone who attempts to explain Oracle's behavior a shill or "unpaid marketing for Oracle".

My experiences with btrfs over the past many years on my laptop and my desktop have been quite good.

I, for one, do want my FS to run on 32-bit systems and, don't want it to require gigs of RAM to get its work done. (My information may be out of date, as I stopped looking at ZFS once it became clear that btrfs was stable enough for the tasks that I was putting it to.)

ZFS does not require gigs of RAM to work, it's ARC that does. You can have ARC disabled, but then ZFS performance isn't that good.

ARC would be perfectly happy with small amounts of memory. ZFS ' ARC implementation will free memory as required by the system (provided that the Linux kernel asks) and grow when memory is not in use up to zfs_arc_max. The limit is completely configurable and can be set to something small like 64MB.

32-bit support is a sore spot caused by differences in how Solaris and Linux do memory allocations. Expect to see it fixed in the next 6 months.

That aside, >99% of memory used by ZFS on many systems is used for cache. It does not need that to operate, but like all filesystems, it performs better with more cache.

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