Category: Hammer

Hammer downgrade and upgrade bug


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.

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Hammer disk removal


Thanks to Michael Neumann, it’s now possible to remove a drive from a Hammer volume.  It’s experimental, so all the standard warnings apply.

This can’t be done on a root volume, for hopefully obvious reasons.

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Hammer expanding


Did you know you a Hammer volume can span multiple disks?  And that you can add extra disks later on?  There’s no RAID-like features – it’s just a straight multiple-disk volume, but it works.  The Hammer command to do it is now “hammer volume-add

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

Hammer saves my bacon


Some of the ikiwiki configuration files on dragonflybsd.org were accidentally overwritten during a software upgrade.  Normally this would mean some work to locate and replace them from backups, but since it was a Hammer volume, a quick look in /var/hammer/usr/… found them for me.

I want to point out what Hammer does, here.  Restoring from backup isn’t new – it is in fact probably one of the most basic and necessary of system administration duties.  However, Hammer makes it so easy that the incremental work of using it falls to almost nothing.  There’s no extra preparation or syntax to learn for retrieval, which is wonderful.  Hammer’s easy fix has helped me out several times now, saving me time that, while probably still successful with any other backup system, would have been taken up just restoring things back to normal.

Posted by     Categories: Goings-on, Hammer     2 Comments

Hammer version 4 now available


Matthew Dillon has made version 4 of Hammer the default; the upgrade is a relatively painless ‘hammer upgrade’ command.   This new version cuts out a chunk of the disk syncs needed, speeding up Hammer disk operations.

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

More links again


I like linkblogging, especially because there’s been a lot of good stuff floating about:

Posted by     Categories: BSD, DragonFly, Hammer, UNIXish     2 Comments

Accessing Hammer config via NFS


Thomas Nikolajsen came up with some ideas for making the configuration files for a given Hammer volume accessible, even when that volume is being presented over NFS.  He’s looking for more ideas.

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Small undo fix


If anyone wants a project, there’s apparently a small undo bug that I’ve encountered.  It is a small fix in terms of changes, for any takers.

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Hammer version 4 status


There’s a status report from Matthew Dillon about his work on version 4 of Hammer, including the always enjoyable stories of tests that involve yanking the SATA cable from the drive.

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New Hammer work


Matthew Dillon’s working on a 4th iteration of Hammer, this time to address speed issues, among other things.   There’s a bunch of commits to look at so far.

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

Easier Hammer manipulation


‘mike’ made this interesting csh script that allows autocompletion of Hammer sub-commands.  e.g. type ‘hammer’ and then cycle through the available hammer commands as you would through file names.

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More Postgres benchmarking


Jan Lentfer repeated his Postgres tests on DragonFly with some system changes suggested by Matthew Dillon, and noticed a speed increase.  (See previous report.)

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

Bug report reading


This description of a Hammer bug makes for interesting reading, since it delves into the sequence of events where data is actually laid down on disk.  Interesting reading for a geek, admittedly…

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Hammer version 3 in testing


Version 3 of Hammer is now available in bleeding-edge DragonFly, though it’s still experimental.  The biggest reason for this version bump is to move the /snapshots folder to /var for all Hammer filesystems.  This means an accidental <tt>rm -rf</tt> won’t destroy snapshots, as I’ve done.  The saved data is still on the original partition, as just the metadata is saved to /var.  More explication is available.

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

Postgres benchmarks


Jan Lentfer performed some Postgres benchmarks on DragonFly.  It’s elaborate enough that it’s in the form of a PDF attached to the message I’ve linked. There’s some additional variations that haven’t been tried yet.

Vigorous file system activity seemed to lower performance in the long term on Hammer, which is certainly something to investigate.  More testing please!

Posted by     Categories: DragonFly, Hammer     4 Comments

Saved by Hammer


A script I was running on avalon.dragonflybsd.org yesterday afternoon removed the packages, iso images, and snapshots stored there.   (Sorry!)  Hammer saved my bacon, with a snapshot of the 182G of missing files immediately available.

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Hammer mirror header output, just in case


If you back up the pseudo-file-systems (PFS) on your Hammer volume to a non-Hammer disk, and then need to restore them to a new Hammer volume, and then realize you forgot to write down the shared-uuid, well, then, YONETANI Tomokazu has a patch for you.  I haven’t seen this committed yet, but it appears valuable.

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Hammer speedups


Matthew Dillon’s made some changes to Hammer that make performance during mixed operations (reading and writing requests at the same time) much faster.  This should work for everyone, though AHCI/SILI/SCSI users will notice it more.  The new writing system is called ‘BIOQ‘.

Hammer improvements, tests


Matthew Dillon’s made some improvements to Hammer’s read and write processes.  To quantize this, he’s tested Hammer and UFS with blogbench and written up the results.   The tl;dr summary: UFS performs well until the system cache runs out, and then it halts.  Hammer has some overhead from saving all history, but doesn’t stop working under a much heavier load.

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

Messylaneous: books, lawsuits, git, more


Dear universe, including DragonFly people: stop doing so much stuff.  It’s hard to keep up.

Posted by     Categories: BSD, DragonFly, FreeBSD, Hammer     0 Comments

Spreading Hammer


Want to bring Hammer to Slackware Linux?  People want it, and there’s some work already in progress.

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

PFS and NFS now play nicely together


It is now possible to mount a Hammer PFS via NFS, though you’ll want to use NFSv3.

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

Hammer gets bigger


Hey, look at what Michael Neumann’s doing: making Hammer expandable!  It will be possible to expand your Hammer volumes while online, even.

(note: it’s experimental; don’t be surprised if it destroys data.)

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

New Hammer option


The hammer command now has an ‘info’ option, which gives a great deal of information on your Hammer drives, thanks to Antonio Huete Jimenez.  (Committed)

Posted by     Categories: Committed Code, DragonFly, Hammer     2 Comments

New Hammer version


Matthew Dillon has a new version of Hammer, which speeds up listings from programs like ‘ls -la’ and ‘find’.  This is only in 2.3.1.x code right now, so don’t force an upgrade via hammer version-upgrade if you’re still on DragonFly 2.2. His post includes some benchmarks.

On a side note: sili(4) tests look good.

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

Other ways to back up Hammer


As Jim Chapman found out, dump only works for UFS, and not for Hammer.  Matthew Dillon outlined the different mirroring and snapshot methods that Hammer makes available.

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Mirroring with Hammer


Siju George described his efforts to set up a continuous, automatic backup system using Hammer, with some interesting results.  Matthew Dillon chimed in with some suggestions.

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

Minor Hammer changes


Matthew Dillon’s made some small changes to Hammer; it should result in a small speedup when copying data.

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Better speed for cleanup


A number of people have noticed that Hammer’s pruning (which by default runs once at midnight) makes systems temporarily unresponsive.   Matthew Dillon’s committed a fix for this, with warnings of more improvements to come.

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

Bulk build speed stats


I recently did a bulk build of pkgsrc on two similar machines; the only significant difference being extra CPU work being done on one system, and Hammer snapshots on the other.  However, they’re diverging in speed over time, which is interesting but not yet conclusive.  Read my post about it for more details.

A good benchmarking project would be testing Hammer with snapshots on and with snapshots off.

Posted by     Categories: DragonFly, Hammer, pkgsrc     0 Comments

Hammer presentation at BSDDay


Sdävtaker is giving a “Hammer administration” presentation at BSDDay, May 29th and 30th in Argentina.  (His presentation is the second day.)

Posted by     Categories: Conventions, DragonFly, Hammer     0 Comments

Hammer porting notes


Daniel Lorch, the student working on a port of Hammer to Linux, has a blog, with some notes on progress.  I found this April item entertaining.

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lseek(2) extensions for Hammer?


Pedro F. Giffuni suggested that the SEEK_HOLE and SEEK_DATA lseek extensions would be good additions to Hammer, and linked to a Sun paper that went into more detail.

Posted by     Categories: DragonFly, Hammer     1 Comment

Encryption ideas for backups


Sdävtaker came up with a potential idea for encrypting backup files, and Matthew Dillon followed up with another way that uses Hammer.

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

Hammer for Linux, and others


Daniel Lorch is working on a port of Hammer to Linux’s VFS, though since he’s using FUSE, it will be able to reach other systems, like NetBSD.  The code is accessible.

Posted by     Categories: DragonFly, Hammer, NetBSD     0 Comments

Lost any Hammer files?


Matthew Dillon is trying to track down a Hammer bug where directory entries (files, usually) are missed, whether it’s with ls or find or similar.  Has this happened to you?  It’s apparently very hard to duplicate, so please speak up if it has.

Posted by     Categories: DragonFly, Hammer     1 Comment

DWIMmy undo


Hammer’s ‘undo’ now has the ability to index and automatically diff historical versions of files for you, thanks to a patch from Joel K. Pettersson.  (He’s got more ideas, too.

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

Hammer for Linux?


Simon ‘corecode’ Schubert has a student working on a Linux port of Hammer.  This will lead to a breakout of Hammer from the DragonFly tree, too.

Posted by     Categories: DragonFly, Hammer     4 Comments

New Hammer feature


Matthew Dillon has added a “rebalance” feature to Hammer, which cleans up the underlying B-Tree structures in Hammer that might otherwise slow down searching. It’s considered experimental, so be careful with it for now.

Posted by     Categories: Committed Code, DragonFly, Hammer     2 Comments

Messylaneous, 03/12/2009


A bunch of links, cause that’s the easiest way to get this all out:

Posted by     Categories: DragonFly, Hammer     2 Comments

Hammer this, Hammer that


Hammer filesystem, meet Hammer OS.  Please don’t take this seriously.

Posted by     Categories: DragonFly, Hammer     2 Comments