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Anyone tried DragonFlyBSD / Hammer FS?

Posted: 2013-05-31 20:26
by confuseling
DragonFly caught my interest a while ago with Hammer FS, which by all accounts is pretty astonishing considering how small its development team is.

However, last time I installed it in a VM it didn't seem to have a huge amount of software available to it without compilation - it used the same pkgsrc ports as NetBSD, which are fairly extensive, but there seemed to be a lot of build failures or something... Not too sure, I didn't dig into it in detail, but many for me key applications were missing (and I wasn't really interested in compiling everything).

The most recent release has switched over to pkgng from FreeBSD for its primary package management, and seems to have plugged this gap.

And Hammer is really, really clever. You can configure a retention policy, so for example all files / directories / entire filesystems can be accessed as they were at any point in the last few months (with something like 30 second to 1 minute granularity), or files can be accessed by specific revisions. Obviously this takes up space, but it isn't egregiously heavy - and its RAM / CPU load is nothing like ZFS's. It's reckoned to work reasonably well on anything with more than 512M of RAM and 50G drive space.

Worth looking at.

Re: Anyone tried DragonFlyBSD / Hammer FS?

Posted: 2013-05-31 22:31
by h3z
I haven't tried Dragonfly, but it seems like the the reviews of the hammerfs are consitently in the possitive. At least from the reviews I have read. I haven't done any excessive research into it either. I think that the hammerfs is one of the primary focuses of the Dargonfly team. So, it is no surprise to me that they have come as far as they have. Especially when considering the members of its development team. Pkgng is the future for FreeBSD, but I hope to see pkgsrc survive and thrive as it is a great tool for all independent platforms and infant distributions. It can even be used under a Linux kernel. I believe that the Dragonfly team still views the hammerfs as experimental, but notably stable.

Re: Anyone tried DragonFlyBSD / Hammer FS?

Posted: 2013-06-01 17:04
by confuseling
It's the default FS for DragonFly, and I think the team consider DragonFly production-ready.

Here is an example of the voodoo you can do with it:

http://www.dragonflybsd.org/docs/docs/h ... nhammerfs/

For a normal desktop / workstation user, that looks a heck of a lot more useful than anything BTRFS / ZFS can do (I don't doubt that with clever scripting you can get similar things out of ZFS, but my experiments with it have persuaded me that it's more of a data-centre filesystem, in need of a serious sysadmin (not to mention a fairly obscene amount of RAM) to realise its potential. This may simply be lack of knowledge on my part).

The principle focus of DragonFly historically was transparent clustering - basically to be able to install the 'same' OS on multiple different computers, and have them share resources between them without the user having to do anything. The filesystem is designed accordingly.

Re: Anyone tried DragonFlyBSD / Hammer FS?

Posted: 2013-06-02 13:23
by h3z
After looking around their site, I'd say you are likely correct. They seem to have come a long way, since my last peek.
Maybe one day kfree will come with the option to use hammerfs.