Hammer – Page 6 – DragonFly BSD Digest

2012/09/232012/09/22

Lazy Reading for 2012/09/23

The weather is finally turning cooler, which makes me happy.

I don’t think I’ve seen this before: Very old UNIX releases, listed for running in emulation. (via)
Where the red-black tree name came from. A red-black tree underpins Hammer 1’s data structures, though it does not in Hammer 2. (also via)
Someone with a HP passport login want to help this guy? He just needs to reinstall Windows in IDE mode, or perhaps find the right sysctl to toggle.
The acme editor, from Plan 9. I didn’t realize it’s 20 years old.
Speaking of editors, Replace in Multiple Files with Vim. I haven’t seen the argdo command before, or the Vim Ninjas site. Their color schemes article is useful just for the screenshots. (via)
Adbuntu. It’s not as bad or as inconsequential as most reactions would lead you to believe, but advertising within an OS seems heavy-handed. The BSD model has been to use the operating system as a vehicle for selling hardware, and that’s been much more successful. (see iOS, PC-BSD.)
Where Did the Internet Come From?
The map for Adventure. (via)

Your unrelated link of the day: Victorian Sci-Fi. It’s not just a reference list, it’s a link to a lot of the original material, since copyright no longer applies.

2012/09/142012/09/14

Do you have offline Hammer1 slave systems?

If you do, they don’t get cleaned up during the normal ‘hammer cleanup’ nightly routine. Chris Turner has added a way to manually specify them as a cleanup target.

I’m pretty sure in this case ‘offline’ means ‘nothing streaming to it from a master disk’. I think.

2012/09/122012/09/12

Some new Hammer features: scoreboards, shells

These are small, but they make life easier: Hammer now has a scoreboard file, for viewing of mirror-streams running in the background. There’s also a ssh-remote directive, so you can use ssh without enabling an interactive shell, and a HAMMER_RSH environment variable so different remote shells can be used. These are all for Hammer 1.

2012/08/262012/08/26

Lazy Reading for 2012/08/26

There’s certainly no theme to this week’s links. I even manage to avoid my usual git and vim links, strangely.

Ethernet’s Future: How Fast Is Fast Enough? The article doesn’t answer any questions, but I like the IEEE-supplied graph it opens with that shows the trend of overall network traffic doubling yearly. (via)
Anti-open source propaganda in Disney kids’ TV show. I’m actually more bothered by trying to hyphenate a phrase made from separate words. Anti-‘open source’? Esoteric grammar issues appeal to me.
Bash One-liners Explained, part 3.
Perl hex and bit pack formats were added to fix the Magellan satellite’s output. A neat origin for something I’ve used trivally. Of course, I suppose any use is trivial compared to fixing output from a broken spaceship. (via many places)
Here’s a DragonFlyBSD article from 2010 linked on Hacker News. The ensuing conversation in the Hacker News comments is lucid and useful, and not a single bit of whining about BSD being dead. That’s so refreshing to see!
Looks like there will be a new version of ADOM. Will it run on DragonFly? It should, since the previous version is in pkgsrc.
Do you like set theory? Then read this. I don’t understand a word of it, but I like seeing the mathematical characters encoded on the page, apparently using MathJax.
I also enjoy reading about BSD users’ origin stories. In this case, Dru Lavigne.
CDE has been open-sourced. There’s a good chance it will show up in pkgsrc soon. Seeing this interface will make you nostalgic if you are the right age.
If you’re a fan of the Hammer filesystem, does that make you a hammerhead? That’s my weak attempt to segue to this comic.
Artisanal, hand-crafted unsigned ints. Read the bottom of the About page for an explanation. This may not make sense to you if you haven’t encountered the trend it’s making fun of, which seems to be centered in Brooklyn. (via)
I hope you enjoy scrolling, because this history of computers and history of computer graphics are very long single documents. I like seeing the early computer art. (via)

Your unrelated comic link of the week: Cul De Sac. The strip is ending due to the creator’s health issues, but what he has done is marvelous. This is one of the few newspaper strips that is both visually interesting and often abruptly laugh out loud funny, without being patronizing.

2012/08/172012/08/17

Actually trying Hammer 2

If you wanted to try Hammer 2 and you have several DragonFly-current systems around (virtual or not), Matthew Dillon has the instructions. Keep in mind that this is not something ready for use; it can’t actually free up space, for instance. It’s neat that you can have multiple systems passing data back and forth already, though!

2012/08/14

Hammer 2 status report

Matthew Dillon recent posted a status report for Hammer 2. Of interest is the spanning tree protocol being built to handle messages between Hammer volumes. As he says in the message:

For example, we want to be able to have millions of diskless or cache-only clients be able to connect into a cluster and have it actually work…

(No, it doesn’t do this, yet.)

2012/08/04

Hammer 2 messages

Hammer 2 (or is it HAMMER2?) is nowhere near ready to test. But! For laughs, I think it could be set up just so you can watch the messages go back and forth. Someone want to set up a few DragonFly-current VMs and try?

2012/06/09

HAMMER2 and remote mounting

Reading this HAMMER2 commit carefully shows some future plans: remote cluster control, and the ability to mount nonlocal HAMMER2 volumes. A reminder: those are future plans, not what you can do now.

2012/06/05

CCMS goes away, comes back

The cache coherency management code in DragonFly has been removed, but it’s coming back under HAMMER2, as part of how HAMMER2 maintains multiple master drives.

2012/05/192012/05/18

More on HAMMER2 progress

As noted in a recent commit, it’s possible to set up a HAMMER2 /usr/obj and survive a buildworld. That’s good progress.

Note that this is basic work, so features like multi-master and deduplication are not present yet, and it’s still work in progress, so don’t try HAMMER2 unless you like losing data. Watch the branch for changes, though.

(I’m going with “HAMMER2” for the name.)

2012/05/16

Hammer 2 progress

Matthew Dillon’s recently added getaddr/setaddr support, dumping, and session encryption, among other things, to Hammer 2. Or is it HAMMER2? I’m not sure.

2012/04/13

Hammer2 messaging

If you’re curious about Hammer2 development, it’s been ongoing, but there haven’t been any more juicy commits to point at. Here’s one – the start of the messaging system.

2012/02/29

Deleting too fast

Here’s an interesting side effect that came up in Hammer 2 development: deleting files can potentially require modification of only one parent element. If I’m reading it right, that means deletion always takes about the same time, independent of the amount of data being deleted. Your ‘rm -rf /largedrive’ could complete, removing multiple terabytes of data before you realize it. I suppose it’s silly to complain about speedy results. Of course, being Hammer, it would still be available in history.

2012/02/092012/02/08

Hammer 2 branched

There’s a Hammer 2 branch in the DragonFly git repo now, for the next generation of DragonFly’s native file system. Don’t get too excited; as Matthew Dillon explains, it won’t be operational for months, and features won’t get added until much later this year. It’s neat to see the work happening, though, and there’s a new design document to show what’s coming.

2012/01/192012/01/17

How low can you go? (with RAM and Hammer)

Matthew Dillon has a very detailed commit message with changes to make sure Hammer will run overnight cleanups in situations as low as 256M of RAM. I think you can find that much RAM in breakfast cereal boxes these days.

2012/01/022012/01/02

How much RAM is too little?

If you’re running DragonFly on a very low-end system, you may be wondering about memory requirements for Hammer. Hammer is much less RAM-hungry than ZFS, so it looks like you can get away with 128M, as long as you don’t mind the occasional error message. You can manually tweak settings for it if you like. 256M is plenty.

It still strikes me as odd to consider systems with less than 1G of RAM as “low-memory”. What rich times we live in!

2011/10/31

Libhammer added

Antonio Huete Jimenez’s ‘libhammer‘, a library to make various Hammer functions available to userland programs, has been added. It implements ‘hammer info’ only at this point, if I understand correctly.

2011/10/262011/10/26

A new Hammer presentation

Francois Tigeot recently presented a set of slides about Hammer at a recent Irill conference. PDFs of the slides are available at his site, in English and French.

2011/08/19

Quotas almost sort of working

Francois Tigeot took an old Summer of Code proposal, VFS Quotas, and started running with it. He’s made some progress, as he detailed in a recent post to kernel@ (with code!) , but the nullfs-mount nature of PFSs in Hammer are making it difficult.

2011/08/132011/08/08

Deduplication now eats less RAM

Well, if you tell it to do so. Matthew Dillon has added a user-settable limit to the amount of memory used during deduplication, so if your Hammer-using system is low on RAM, you can conserve. This is probably most useful if you are running DragonFly in an extremely small VM, or if your name is Venkatesh.

(inside joke; Venkatesh has a crazy old desktop for DragonFly.)