You have probably seen reports declaring the demise of OpenSolaris by now, many taking a less than conservative approach in reporting the news one way or the other. So what do you make of the news? By all accounts, the source code (including future changes) for things such as ZFS will continue to be published under the CDDL. Will Oracle closing up development make it impossible for operating systems like FreeBSD to maintain ZFS without forking it? What do you think the ramifications will be for DragonFly’s HAMMER and DragonFly in general?
Matthew Dillon made a minor change to HAMMER that would help any future deduplication work. There’s also a deduplication code bounty out on the recently-updated Code Bounties page…
I’ve been NAS-shopping, and I’ve found that deduplication ability seems to add an extra zero on the end of a device’s price tag. It would be very nice for HAMMER.
I apologize; I’ve been missing. Here’s some misc links while I get back in gear:
- A very good reason to be interested in Hammer over ZFS: nobody will threaten lawsuits over Hammer.
- 10 tricks for admins. I’m posting it cause I can never remember that thing with tunneling ssh out. (via)
- This Gaming Life, as a free download. An excellent book that is in physical form on my shelf right now. Yes, unrelated.
If you have a Hammer filesystem, and you want to roll the entire thing back to a previous snapshot – all files, everywhere – it can be accomplished with one command.
A note, in part for my own benefit: the @reboot crontab entry is all you need to get a HAMMER mirror-stream going again after a reboot/shutdown.
Matthew Dillon went into detail on just how Hammer snapshots could be shared out via Samba.
Siju George is making a Hammer volume’s snapshots available through Samba, with the results that some Windows-using developers get historical snapshots for free.
Matthew Dillon identified a possible data corruption bug in Hammer with a nearly-full filesystem. It’s dramatic enough he’s tagged 2.6.2 and 2.7.2 so that people can update; his message about it describes how to check for corruption.
If you’re worried that your Hammer disk may be going bad – and I mean bad like physically bad – you can check it with dd, or see what the hammer tool lists as bad.
Jan Lentfer’s done some new benchmarking of PostgreSQL on Hammer. There’s further suggestions and a more complete benchmark is planned, taking advantage of the Hammer improvements in 2.6. In the meantime, you can look at previous benchmarks.
Daniel Lorch has ported Hammer to Mac OS X, of all things. It’s not complete, but he’s moving right along.
Daniel Lorch’s work on porting Hammer to Linux (read-only, currently) has been moved to a new location.
Matthew Dillon has implemented what he calls “REDO” records in Hammer, which reduce the amount of time taken flushing data to disk. It’ll be in the 2.6 release, but it isn’t on by default.
Jordan Gordeev’s work on 64-bit vkernels has also been brought in, so virtual systems are now available for x86_64 users.
Michael Neumann has fixed the ability to stream Hammer data between 32 and 64 bit systems. However, this is a change to 64-bit systems that requires them to match; make sure that you are not mixing 64-bit systems built before and after this commit on the 21st.
I can’t find the commit message in the mail archive, so I’ll quote it here:
Pulled from a larger conversation: a description of the settings for a HAMMER filesystem, and what they mean. I can tell from experience that extremely active disks will need extra cleanup time…
I can’t keep up with all the things to post. I desperately want to clear my inbox, so here’s a week’s worth of posts all smushed together. Enjoy!
- Naoya Sugioka’s tmpfs work is almost ready to go.
- Francois Tigeot is looking to find supported RAID hardware for DragonFly; the LSI1068e isn’t useable. Freddie Cash listed a number of different and fully supported cards, and Francois listed some other potential choices.
- While talking about hardware, Steve O’Hara-Smith reported excellent results with a particular Atom 330-based board and DragonFly.
- Stathis Kamperis has added to ‘hammer snapls’ output; an example is in his submit@message.
- The 2.6 release of DragonFly, scheduled for March, will have version 4 of HAMMER. 2.4 has version 2. Upgrading from version 2 to 4 can happen in place, live, and only needs to happen once per volume, not per PFS. That’s about as easy as it gets. More details are available.
- The default sshd config has been updated; this shouldn’t affect your normal operations unless you’re using one of the mentioned options.
- Oliver Fromme linked to more discussion of SSD durability.
- Also, Matthew Dillon posted more notes and benchmark numbers for his swapcache work. There’s been some side benefits too. A man page for swapcache is now available.
- Aggelos Economopoulos’s libevtr has been added, for event tracing. He’s posted some additional notes on this work-in-progress.
- We now have /var/log/daemon, too.
- Notes on prepping for Google Summer of Code 2010 from the GSOC Discussion list; I don’t know if that link is readable for nonsubscribers.
- The Definitive Guide to PC-BSD is out at the end of this short month. Dru writes good books.
- Did you know FreeCiv (a Civilization clone, of sorts) is playable in a web browser? Goodbye free time! Details are available at my favoritest game site.
Phew.
Michael Neumann presented a talk on HAMMER at the Karlsruher Institut
für Technologie on January 27th. His slides (in English) are now available in PDF or ODP formats, and are listed on the dragonflybsd.org Presentations page.
If you’re running DragonFly 2.5 and updated in the past week or so, and have UFS disks, there’s some instability introduced by Matthew Dillon’s recent work. It ought to be better by next week.
Users of Hammer, or of UFS only as /boot, don’t have anything to worry about.
That didn’t take long: Matthew Dillon has an update on his REDO work; he’s about halfway there. His summary includes instructions on how to test this new work, including ways to change how Hammer syncs to disk.
Thomas Nikolajsen experienced firsthand a bug where downgrading a Hammer PFS master to a slave and then later making it a master again lost all data. Lucky him… The problem’s now fixed.