Category: Hammer

Clustering and copies in HAMMER2

Matthew Dillon answered some mailing list questions on how clustering and data copies will work in HAMMER2 – no due date, of course, because this is very complex.  If you’re really into it, there’s always watching the recent commits.

Posted by     Categories: DragonFly, Goings-on, Hammer     2 Comments

Got Nagios? Got Hammer?

If you’re monitoring your DragonFly systems with Nagios, here’s a way to check the health of your Hammer mirror-streams.  Thanks, Mike!

Posted by     Categories: DragonFly, Hammer     0 Comments

DragonFly catchup

Here’s a number of DragonFly links to clear out my backlog:

Posted by     Categories: DragonFly, Goings-on, Hammer     2 Comments

ZFS and Hammer conversation

There’s a FreeBSD Forums thread about ZFS and Hammer, as several people have pointed out to me.  It’s interesting to see, but there isn’t a lot of quantitative discussion.  (It’s a forum post, not a white paper, though.)

Posted by     Categories: BSD, DragonFly, FreeBSD, Hammer     4 Comments

Slider, for Hammer

John Marino has created something very useful: a graphical tool for Hammer file history.  It’s called ‘Slider’, and it uses curses to work in a terminal.  It shows historic versions of files and can restore those old versions as needed.  This was already possible in Hammer, of course, but it required a sequence of commands that were not straight-forward.  I’ve been slow enough posting it that version 2.0 is already out, offering a way to see files that no longer exist, but are still in history.  (i.e. deleted some time ago)  ‘Time Machine’ sounds like the best name, but that seems to be taken.

A tip for Hammer disks and history

One way to keep file history on an very active Hammer disk from eating up all the space: more snapshots.  This may seem counterproductive, but disk pruning eliminates historical data between snapshots, so you can keep older data at the cost of some temporal accuracy.

BSDNow 053: It’s HAMMER Time

Not the first time that pun has been deployed, of course, but: BSDNow 053 has a Hammer tutorial, along with an interview of Reyk Floeter about OpenBSD’s httpd, along with the usual recent news and some links to some things I haven’t seen, like pfSense tricks.


Posted by     Categories: BSD, Hammer, Periodicals     0 Comments

Hammer and mirrored disks

A frequent question people ask when trying Hammer is “How can I do software RAID to cover a disk failure?”  Hammer provides for streaming one volume to another, so you can duplicate drives, but there isn’t an automatic failover mechanism as there is with a RAID setup.  The first answer is usually “get hardware RAID“; my preferred solution.   The remaining software solutions are vinum, ccd, and lvm for DragonFly.

Posted by     Categories: Device support, DragonFly, Hammer     4 Comments

How to keep Hammer empty

A note for everyone: use Hammer default on a very busy filesystem, and you will eat a lot of disk space since all file changes are recorded.  (I’ve done this to myself a few times.)  Francois Tigeot has a list of tips on how to keep that from happening.

Hammer and buffers

Are you running a Hammer filesystem on a low-memory system?  You may get some warnings.  It’s possible to tweak some settings to accommodate it, or just deal.

Hammer in BSD Magazine

The May BSD Magazine is out, and Siju George has written an article about using Hammer on DragonFly.  It’s a free download to read.

(link fixed)

Posted by     Categories: BSD, DragonFly, Hammer, Periodicals     3 Comments

BSD Magazine for March

The March issue of BSD Magazine is out, and this month has an article written by Siju George about how his company is using DragonFly and Hammer for backups.

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Hammer 2 work and notes

Matthew Dillon committed the start of a Hammer 2 cluster API. I noticed, while looking at the commit, that there’s a design document, a freemap design document, a changes list, and – most important for anyone interested – a TODO list.

Posted by     Categories: DragonFly, Hammer     2 Comments

Backing up Hammer to non-Hammer volumes

Hammer’s ability to stream to remote disks is great, but what if you have storage that uses some other file system?  Antonio Huete Jimenez put together a shell script that will dump out the contents of a Hammer PFS, for upload to whatever.  Read the README for the details.

Remember: manually clean up offline Hammer volumes

If you have a Hammer volume that is offline, meaning that you don’t have the pseudo-file-systems null-mounted anywhere, it won’t get cleaned up in overnight processing.  You just have to manually specify it.

Hammer2 status

This is a little old, but Matthew Dillon noted the status of his Hammer2 work a little while ago.  Some highlights: he’s intending Hammer2 to be usable on a single host by the time of the next DragonFly release (summer 2014), the Summer of Code project for compression has already been integrated, and he listed different parts of the work that may be interesting for anyone wanting to chip in.

Slightly related: Matt posted some Hammer2 comments on the DragonFly 3.6 release story on Slashdot that may be interesting.  Don’t bother reading the other comments; they’ll make your eyeballs bleed.

Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

Hammer2 boot support

If you want to boot from a Hammer 2 /boot volume, you now can.  Hammer 1 never worked well as /boot, though it was technically possible.  Hammer 2 will be just fine.

Note that you can’t turn on recently-added disk compression since the bootloader doesn’t understand it, and Hammer 2 is not ready for anything but being worked on.  Don’t try it unless you’re ready to be submitting code changes to fix Hammer2.

Posted by     Categories: DragonFly, Hammer     0 Comments

Deduplication benefits, again

Remember my recent disk issues?  As a side effect of protecting myself, I have a good example of deduplication results.

I have a second disk in my server, with slave Hammer PFSs to match what’s on my main disk.  I hadn’t put them in fstab, so they weren’t getting mounted and updated.  I got them re-created, but they were nearly full.  Here’s an abbreviated df, from which you should be able to tell which drives I have :

Size   Used   Avail   Capacity
929G   729G   200G    78%    /slave/slavehome
929G   729G   200G    78%    /slave/slavevar
929G   729G   200G    78%    /slave/slaveusr
929G   729G   200G    78%    /slave/slaveslash

That 78% is how full the Hammer volume was.  I turned on Hammer deduplication, since it’s off by default.  The very next day:

Size   Used   Avail   Capacity
929G   612G   318G    66%    /slave/slavehome 
929G   612G   318G    66%    /slave/slavevar 
929G   612G   318G    66%    /slave/slaveusr 
929G   612G   318G    66%    /slave/slaveslash

It’s a 1 terabyte disk, and I gained more than 10% back – That’s 100g of disk space that I gained overnight.  There might be more tomorrow, given that it was all of 5 minutes of dedup work.

This won’t surprise you if you’ve seen previous deduplication links here, like my previous results or some real-world tests.  It’s still great.  I’d suggest turning it on if you haven’t – hammer viconfig the appropriate PFS and uncomment the dedup line.


Posted by     Categories: DragonFly, Hammer     1 Comment

Hammer and Go

Something new and odd: A port of the Hammer (1) filesystem into Go, for go-fuse.  As the author has said, it’s more for the practice of learning Go and Hammer than for producing anything useful.  Still, an interesting way to learn.

Posted by     Categories: DragonFly, Hammer     1 Comment

Hammer 2 and encryption, briefly

Encryption seems to be the accidental theme tonight.  A question about Hammer 2 and encryption prompted this list of possible solutions from Matthew Dillon.  Hammer 2 is still months out, so these features both require time and someone interesting in doing them – though they sound quite possible.

Still not sure if I should be writing Hammer or HAMMER.

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Encrypting /home

If you were wanting to encrypt your /home directory, Pierre Abbat has written up the explicit steps he took to do that very thing.

Posted by     Categories: DragonFly, Hammer     0 Comments

GSoC Hammer and compression performance numbers

Earlier this week, Daniel Flores posted the first-week report on his Google Summer of Code project, file compression in Hammer.  He mentioned that the LZ4 algorithm he is using seems to have the best performance with repeating text data, as in logfiles.  I asked for numbers, and he provided them.  The important data in the results is the total compression column.  It shows how many 64k blocks were able to be compressed, with that type of data.

Posted by     Categories: DragonFly, Google Summer of Code, Hammer     0 Comments

Many upgrades, and Hammer

John Marino managed to update GCC from 4.7.2 to 4.7.3 (4.7 changelog), zlib from 1.2.7 to 1.2.8 (changelog), and awk from 20110810 to 20121220 (can’t find a changelog).

In other update news, Matt Dillon has been working on HAMMER2’s flush sequencing.

Update: tcsh too.

Posted by     Categories: DragonFly, Goings-on, Hammer     1 Comment

HAMMER file system resizing

If you’ve ever wondered about how you can resize/move a HAMMER filesystem, follow this thread for a variety of answers.

Some Tux3 notes

If you’ve been feeling the need for reading about filesystems, Daniel Phillips has posted more notes about his Tux3 filesystem design, which can be contrasted with HAMMER.  (thanks, Venkatesh Srinivas)

Posted by     Categories: Goings-on, Hammer     0 Comments

HAMMER2 update

Matthew Dillon has written up another update on his progress with HAMMER2.  (I need to be consistent in how I write that.)  He has disks being exported and mounted on other systems, and adds an explanation of some of the issues around creating reliable multi-master setups.  Before you get too excited, no, multi-master isn’t working yet, and this is not production ready.

Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

More Hammer2 work

Matthew Dillon’s committed a bunch more Hammer2 work.  No, it’s not usable yet.  Look at the commit messages for details on how he’s setting up multi-master volume information, though.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

More Hammer 2 in the tree

Matthew Dillon’s put more of his Hammer work into DragonFly, with notable parts being the creation of a ‘dmsg’ setup for advertising available block devices to share between machines using Hammer.  To anticipate your next question: No, it’s not something you can run right now as a test; this is the underlying framework.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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.

Posted by     Categories: BSD, Hammer, Lazy Reading, roguelike     1 Comment

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.

Posted by     Categories: Committed Code, DragonFly, Hammer     1 Comment

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.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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.

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.

Posted by     Categories: Hammer, Lazy Reading, pkgsrc, roguelike, UNIXish     1 Comment

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!

Posted by     Categories: DragonFly, Hammer     2 Comments

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.)

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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?

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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.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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.

Posted by     Categories: DragonFly, Hammer     0 Comments

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.)

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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.

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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.

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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.


Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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.

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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.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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!

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.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

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.

Posted by     Categories: Conventions, DragonFly, Hammer     0 Comments

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.

Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

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.)


Posted by     Categories: Committed Code, DragonFly, Hammer     1 Comment

Pulse-width modulated time-domain multiplexer!

I really just like that phrase and the action movie feeling of using it, like “Watch out!  The pulse-width modulated time-domain multiplexer is targeting us!”  Sorta like a PU-36 space modulator.  It’s actually a recently-committed mechanism to improve write performance in Hammer, but my idea sounds more exciting.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

Deduplication real world results

I’ve posted about my own results with Hammer deduplication here before, but Siju George put together results from his workplace using actual files in production.  He recovered 138G from a 1T disk, and recovered 20% of space from another disk.  Not bad for something that’s nearly automatic, and completely free.

Posted by     Categories: DragonFly, Hammer     1 Comment

Trying out deduplication

I moved to DragonFly 2.10 over the past few days, and I tried out deduplication, to see what kind of results I would get.  The procedure is outlined below.  I’m using /home here as an example, just to reduce the amount of text pasted in.

/pfs/@@-1:00004     966000640 566434576 399566064    59%    /home

Move my various Hammer pseudo-file systems to version 5, which supports deduplication.

# hammer version-upgrade /home 5

Issue a deduplication simulate command, to see what it guesses will be the savings:

# hammer dedup-simulate /home
Dedup-simulate /home: objspace 8000000000000000:0000 7fffffffffffffff:ffff pfs_id 4
Dedup-simulate /home succeeded
Simulated dedup ratio = 1.22

That ratio turned out to be pretty accurate for the actual deduplication.  I didn’t time it, unfortunately.  I don’t know if the time taken is proportional to the amount of deduplication or the total volume of data, though I suspect the latter.

# hammer dedup /home
Dedup /home: objspace 8000000000000000:0000 7fffffffffffffff:ffff pfs_id 4
Dedup /home succeeded
Dedup ratio = 1.22
462 GB referenced
378 GB allocated
14 MB skipped
6869 CRC collisions
0 SHA collisions
0 bigblock underflows

The end result?

/pfs/@@-1:00004     966000640 505887504 460113136    52%    /home

That data space is shared across all file systems, and it’s a 1TB disk, so it’s 7%, or 70GB. I was hoping for more, but I don’t have any obviously duplicated data (no local mail store, no on-disk backups), so perhaps this is normal. 70GB that I didn’t have before is no bad thing, though.

Incidentally, I was able to upgrade my installed software from pkgsrc-2009Q4 to pkgsrc-2011Q1 entirely using pkg_radd -u <pkgname>.  Remarkably quick and painless, though pkgin may have been able to do it even faster since it would pull from the same place.

Posted by     Categories: DragonFly, Google Code-In, Hammer, pkgsrc     1 Comment

Hot-swap and a bad disk

If you follow this thread, it has some discussion on how to handle a multi-disk setup and Hammer.  If a disk is going bad, you can try mirroring, though you have to be careful how your pseudo-file systems are set up.

Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

More on Hammer design

I mentioned it before, but Matthew Dillon’s updated his Hammer document, and posted about it.  Read on, especially if you like extremely complex plans.

Edit: first link fixed, plus there’s a followup.

Posted by     Categories: DragonFly, Goings-on, Hammer     4 Comments

Remember to enable deduplication

I didn’t think of this, but I needed it: if you have an older Hammer system that now can perform deduplication because you upgraded to DragonFly 2.10, make sure to add it to the configuration for that file system, or else it won’t run.

SSDs and how to portion them

There’s been some discussion on buying a SSD and how to match it with a hard disk, and/or swapcache.  Follow the thread for more details.

Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

Hammer and the future

Matthew Dillon’s been thinking about Hammer, and how to implement clustering well enough to work as a sort of RAID replacement.  He’s written up a document describing his plans.  Some highlights:

  • writable history snapshots
  • quotas and accounting
  • live rebuilds of data from mirrors
  • and the same history, mirroring, and snapshots as before.

It’s going to be a while before this “Hammer 2″ becomes a finished product, though, so don’t count on it for the next release.

Posted by     Categories: DragonFly, Google Code-In, Hammer     5 Comments

RAM vs. deduplication

Tomas Bodzar asked about RAM usage with Hammer and deduplication, pointing at this example that shows ZFS requiring…  I’m not sure.  Lots?  Anyway, Matthew Dillon noted that offline deduplication in Hammer would use available RAM/swap for CRCs on all files, but only a limited subset for ‘live’ dedup.  For a real-world example, Venkatesh Srinivas described deduplicating about 600G down to 400G, with a machine having only 256M of RAM. Yes, only 256M.

Posted by     Categories: DragonFly, Goings-on, Hammer     1 Comment

More Hammer documentation

Thomas Nikolajsen has put together more information on Hammer, including formatting and the new deduplication features, conveniently located in the man pages and some other spots.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

Double buffering in Hammer usually useful

Enabling the vfs.hammer.double_buffer=1 sysctl will greatly improve Hammer performance when you’ve exceeded your memory cache (at a possible slight penalty when you have not) and also speed things up when using live deduplication.

Update: Venkatesh Srinivas says:

“double_buffer makes sense when: 1) you want all CRCs to be checked on reads. 2) you’re running live dedup and care about dedup performance rather than say read-heavy performance; 3) you have swapcache but are often running into the  vnode limit in what you can cache.”

So, not always useful.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

Hammer speed improvements

Yeah, so those Phoronix benchmarks are crap, but Matthew Dillon went and implemented some things that would speed up Hammer write performance in any case.  Read his summary for details.

Posted by     Categories: DragonFly, Hammer     1 Comment

New Hammer version

The default Hammer version in DragonFly is now version 5, which is the one that includes deduplication.  Enjoy, bleeding-edge users!  Otherwise, wait for the next release.

Version 6 is there, but don’t upgrade to it yet; there aren’t significant user-visible changes, and the usual disclaimers for new versions apply.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

Phoronix benchmarks for Hammer

A Phoronix test of DragonFly’s Hammer filesystem turned  up, via Siju George.  It’s not really a benchmark as much as it is a speed test, and it’s not a realistic comparison, but it’s interesting to see numbers.

They need a graph that shows how much historical data can be recovered by each file system, or how long fsck takes after a crash.

Update: Matthew Dillon points out the many ways these tests are wrong.

Posted by     Categories: Goings-on, Hammer     1 Comment

Deduplication arrives

Ilya Dryomov’s work on deduplication for Hammer has been committed to the tree in an early test form.  I guess I need to pay up as part of the code bounty.  If you’re wondering how much space it will save, but don’t want to try non-production code yet, there’s a ‘hammer dedup-simulate’ command that will estimate the saving ratio.

This is great news – deduplication is so valuable it adds an extra zero onto the price of any storage device that can do it.

Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

Encrypted HAMMER volumes possible

I haven’t covered this enough: thanks to Alex Hornung, it’s possible to create a HAMMER volume and have it be encrypted.  Matthias Schmidt has done just this, and has provided an rconfig(8) script to automate the process.  (Or to crib from if you prefer to do it by hand.)

Posted by     Categories: DragonFly, Goings-on, Hammer     2 Comments

Lazy reading: the return of ACID, SSI, weirdness

    A smaller set of links, but still the same volume of reading material.

    Posted by     Categories: Hammer, Lazy Reading     0 Comments

    Updates and improvements for HAMMER, crypto

    Matthew Dillon posted a summary of recent bugfixes in HAMMER and kqueue, which means if you are running a version of bleeding edge DragonFly build in the last few weeks, you should update.

    He also mentions a “significant improvement in performance” in disk encryption.  How significant?  Over three times as fast.

    Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

    New HAMMER catastrophic recovery tool

    Matthew Dillon reports that DragonFly now has a catastrophic recovery tool for HAMMER filesystems, with pertinent details.

    Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

    Summary of recent kernel work

    Matthew Dillon has provided some details about recent kernel work, along with a release forecast.

    Posted by     Categories: Committed Code, DragonFly, Goings-on, Hammer     0 Comments

    What of OpenSolaris?

    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?

    Posted by     Categories: DragonFly, Goings-on, Hammer, Off-Topic, UNIXish     3 Comments

    Dedup, please

    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.

    Posted by     Categories: Committed Code, DragonFly, Hammer     0 Comments

    Messylaneous: reading, catchup

    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.

    Rolling everything back

    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.

    Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

    Keeping a mirror-stream going

    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.

    Posted by     Categories: DragonFly, Hammer     1 Comment

    More on Hammer and Samba

    Matthew Dillon went into detail on just how Hammer snapshots could be shared out via Samba.

    Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

    Hammer via Windows

    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.

    Posted by     Categories: DragonFly, Hammer     2 Comments

    2.6.2, 2.7.2 created; please update

    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.

    Posted by     Categories: DragonFly, Hammer, Heads Up!     4 Comments

    Last-ditch ways to check your disk

    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.

    Posted by     Categories: DragonFly, Hammer     0 Comments

    Even more PostgreSQL benchmarking

    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.

    Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments

    Hammer and OS X

    Daniel Lorch has ported Hammer to Mac OS X, of all things.  It’s not complete, but he’s moving right along.

    Posted by     Categories: DragonFly, Hammer     2 Comments

    New location for Hammer on Linux

    Daniel Lorch’s work on porting Hammer to Linux (read-only, currently) has been moved to a new location.

    Posted by     Categories: DragonFly, Goings-on, Hammer     0 Comments