OpenZFS Project Launches, Uniting ZFS Developers

Damek writes "The OpenZFS project launched today, the truly open source successor to the ZFS project. ZFS is an advanced filesystem in active development for over a decade. Recent development has continued in the open, and OpenZFS is the new formal name for this community of developers, users, and companies improving, using, and building on ZFS. Founded by members of the Linux, FreeBSD, Mac OS X, and illumos communities, including Matt Ahrens, one of the two original authors of ZFS, the OpenZFS community brings together over a hundred software developers from these platforms."

Comments

all i want is BP-rewrite

[Anonymous Coward]

If this gets us BP-rewrite, the holy grail of ZFS i'll be a happy man.

For those who don't know what it is - BP-rewrite is block pointer rewrite, a feature promised for many years now but has never come. It's a lot like cold fusion is that its always X years away from us.

BP-rewrite would allow implementation of the following features
- Defrag
- Shrinking vdevs
- Removing vdevs from pools
- Evacuating data from a vdev (say you wanted to destroy you're old 10 disk vdev and add it back to the pool as a different numbered disk vdev)

Re:all i want is BP-rewrite

[saleenS281]

Because a COW filesystem will become fragmented over time simply by the way it works. As you delete files, you're only free-ing up small segments of contiguous blocks. Over time, this leads to fragmentation because writes are sometimes forced into non-optimal disk placement due to lack of free space. Granted - if you never fill the pool beyond 50%, it won't be a problem. For everyone else, it's a matter of when, not if it will become fragmented.

Re:I'm addicted

[Anonymous Coward]

I love ZFS too, but I'd fucking kill for and open ReiserFS...

Re:Advatages of ZFS over BTRFS?

[Vesvvi]

I don't have any practical experience with BTRFS, but I use ZFS heavily at work.

The advantage of ZFS is that it's tested, and it just works. When I started with our first ZFS testbed, I abused that thing in scary ways trying to get it to fail: hotplugging RAID controller cards, etc. Nothing really scratched it. Over the years I've made additional bad decisions such as upgrading filesystem versions while in a degraded state, missing logs, etc, but nothing has ever caused me to lose data, ever.

The one negative to ZFS (if you can call it that) is that it makes you aware of inevitable failures (scrubs catch them). I'll lose about 1 or 2 files per year (out of many many terrabytes) just due to lousy luck, unless I store redundant high-level copies of data and/or metadata. Right now I use use stripes over many sets of mirrored drives, but it's not enough when you read or write huge quantities of data. I've ran the numbers and our losses are reasonable, but it's sobering to see the harsh reality that "good enough" efforts just aren't good enough for 100% at scale.

Re:If you're successful, Larry will come a callin'

[Bengie]

Oracle released ZFS under a BSD compatible license. Anyone is allowed to do whatever to the opensource code. Going forward, Oracle has not opened an code after v28, which is the last OpenSource version to be compatible with Oracle ZFS.

Re:ZFS for Windows?

[tlambert]

It doesn't have to be POSIX compliant to have it ported to it and it doesn't require somebody to pay for licensing. With the Features of ZFS one could argue that a port to at least Windows Server would be great and it would garnish quite a following from those who've had to put up with the way NTFS views disk volumes and storage.

Windows isn't a very friendly development platform for Open Source, starting with the licensing requirements for tools and distribution restrictions on binaries derived from those tools when using header files containing substantial code, or runtime libraries. Part of this is an intentional legal defense against WINE and CrossOver Office, and part of it is just scale management by limiting the support community requirements to "serious developers".

In addition, a lot of the installable filesystem and similar code, as well as a lot of the necessary VM internals (memory mapped files and paging/swapping from filesystems) are not adequately explained (i.e. they involve locking text regions with level 0 locks, which require a level 3 lock then a level 0 lock, and to do this to get the offsets on the physical media for the blocks in question. This used to not work on removable media in NT as of 4.0.1; not sure if it's supported yet, but it was the reason you couldn't install it in JAZZ drives or even regular hard drives in removable carriers.

Having developed a filesystem for Windows95 IFSMgr, and reverse engineered all this crap, and having done it again for NT3.51, I would not look forward to having to repeat the process for Windows 7 or Windows 8, which are the only useful versions to target for by the time the code ends up functional.

So unless someone wanted to seriously underwrite the effort (read: it's have to be done by Oracle, or by a startup who had a monetization strategy that Microsoft wouldn't preempt, like they did when my team, at a previous employer, ported UFS + Soft Updates to Windows 95, and they announced Longhorn-which-never-happened, and then put together a lawsuit about "deep reverse engineering" which would have precluded using it as a bootable FS... no thanks.

Re:Advatages of ZFS over BTRFS?

[batkiwi]

Nice FUD there. You picked the btrfs-progs, which are the userspace tools, not the actual btrfs filesystem driver.

http://git.kernel.org/cgit/linux/kernel/git/josef/btrfs-next.git/log/