From: Matthew Dillon
Subject: HAMMER update - 12/31/2007
Date: Dec 31, 6:19 pm 2007

HAMMER is progressing well.  The filesystem basically works, but there
    are some major pieces missing such as, oh, the recovery code, and I
    still have a ton of issues to work through... the poor fs blows up
    when it runs out of space, for example, due to the horrible spike 
    implementation I have right now.

    It isn't stable yet but some major milestones have been achieved.  I am
    able to cpdup, rm -rf, and perform historical queries on deleted data.

    Here is a quick example:
    
# newfs_hammer -L TEST -S /var/vkernel/hammerimg.01 /var/vkernel/hammerimg.02
... start up vkernel ...
# mount_hammer /dev/vkd2 /dev/vkd3 /mnt
# cpdup / /mnt/copy
# sync
# hammer now
0x47799042
# rm -rf /mnt/copy
...
# cd /mnt/copy@@0x47799042
[access originally cpdup'd data, even though you deleted it all]

    Please note that HAMMER is *NOT* yet ready for wider testing.  Please
    don't start reporting bugs yet, because there are still tons of things
    for me to work through.

						-Matt


From: Johannes Hofmann
Subject: Re: HAMMER update - 12/31/2007
Date: Jan 1, 1:29 pm 2008

Matthew Dillon <dillon@apollo.backplane.com> wrote:
>    HAMMER is progressing well.  The filesystem basically works, but there
>    are some major pieces missing such as, oh, the recovery code, and I
>    still have a ton of issues to work through... the poor fs blows up
>    when it runs out of space, for example, due to the horrible spike 
>    implementation I have right now.
> 
>    It isn't stable yet but some major milestones have been achieved.  I am
>    able to cpdup, rm -rf, and perform historical queries on deleted data.
> 
>    Here is a quick example:
>    
> # newfs_hammer -L TEST -S /var/vkernel/hammerimg.01 /var/vkernel/hammerimg.02
> ... start up vkernel ...
> # mount_hammer /dev/vkd2 /dev/vkd3 /mnt
> # cpdup / /mnt/copy
> # sync
> # hammer now
> 0x47799042
> # rm -rf /mnt/copy
> ...
> # cd /mnt/copy@@0x47799042
> [access originally cpdup'd data, even though you deleted it all]
> 
>    Please note that HAMMER is *NOT* yet ready for wider testing.  Please
>    don't start reporting bugs yet, because there are still tons of things
>    for me to work through.


Just had to try it myself. This is way cool! Works as advertised - including
the occasional crashes :-)

Johannes


From: Matthew Dillon
Subject: Re: HAMMER update - 12/31/2007
Date: Jan 1, 3:35 pm 2008

:Just had to try it myself. This is way cool! Works as advertised - including
:the occasional crashes :-)
:
:Johannes

    Heh.  Yah, I got too fancy trying to use the buffer cache and I'll
    probably have to rewrite that bit completely.  It also deadlocks fairly
    easily and the kernel sometimes cleans out a buffer without telling
    HAMMER.

    It's going to stay that way for a few days at least, I need to work on
    the userland utilities, the spike code, and the on-the-fly recovery
    code before I can revisit the buffer cache implementation. 

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>