Wow , a lot of interesting features , but the design is too complex when
compared to other BSD s . Isn't it ? Especially the partition naming .... It
requires a lot of time for people like me to understand those concepts ...
thanks a lot for your effort :) Is there any published book on
DragonFlyBSD... i saw the handbook , it is very nice .

On 13 October 2010 17:49, Siju George <[email protected]> wrote:

> On Wed, Oct 13, 2010 at 3:19 PM, Basil Kurian <[email protected]>
> wrote:
> > Hi Siju ,
> >
> > Your reply is so compelling to give DragonflyBSD a try :) Once i
> installed
> > it. Even though i have a little experience with FreeBSD. i was not able
> to
> > manage it. Let me try once more :). It would be nice if you can share
> your
> > blog or something which contains a few howto s .. So that i can start
> with
> > that ... I 'm too excited to try snapshots and  replication feature in
> > Hammer :)
> >
>
> If you have experience with FreeBSD then installing this should be quite
> simple.
> But since you are new I would ask you to try the i386 port if you are
> using it as a desktop.
>
> you can get the cd/usb images from
>
> http://mirror-master.dragonflybsd.org/snapshots/i386/
>
> Installing is simple.
> Just follow through the installer and choose HAMMER when you are asked
> for the file systems.
> Then the installer will automatically create the /usr /var .... etc
> PFses and install everything.
> You have an option to configure "ip details" / "hostname"  etc.
>
> I will tell you some thing about a PFS.
>
> A hammer Filesystem does a lot more than LVM.
>
> If you followed the default options during installation you will be
> left with a system with the following disk configuration
>
> bash-4.1$ df -h
> Filesystem                Size   Used  Avail Capacity  Mounted on
> ROOT                      288G    12G   276G     4%    /
> devfs                     1.0K   1.0K     0B   100%    /dev
> /dev/serno/9VMBWDM1.s1a   756M   138M   558M    20%    /boot
> /pfs/@@-1:00001           288G    12G   276G     4%    /var
> /pfs/@@-1:00002           288G    12G   276G     4%    /tmp
> /pfs/@@-1:00003           288G    12G   276G     4%    /usr
> /pfs/@@-1:00004           288G    12G   276G     4%    /home
> /pfs/@@-1:00005           288G    12G   276G     4%    /usr/obj
> /pfs/@@-1:00006           288G    12G   276G     4%    /var/crash
> /pfs/@@-1:00007           288G    12G   276G     4%    /var/tmp
> procfs                    4.0K   4.0K     0B   100%    /proc
>
> In this example
>
> /dev/serno/9VMBWDM1 is my hard disk secified with UUID
>
> /dev/serno/9VMBWDM1.s1 is the first slice on the hard disk.
>
> Let us see its disklabel
>
> bash-4.1$ sudo disklabel /dev/serno/9VMBWDM1.s1
> # /dev/serno/9VMBWDM1.s1:
> #
> # Informational fields calculated from the above
> # All byte equivalent offsets must be aligned
> #
> # boot space:    1044992 bytes
> # data space:  312567643 blocks # 305241.84 MB (320069266944 bytes)
> #
> # NOTE: If the partition data base looks odd it may be
> #       physically aligned instead of slice-aligned
> #
> diskid: e67030af-d2af-11df-b588-01138fad54f5
> label:
> boot2 data base:      0x000000001000
> partitions data base: 0x000000100200
> partitions data stop: 0x004a85ad7000
> backup label:         0x004a85ad7000
> total size:           0x004a85ad8200    # 305242.84 MB
> alignment: 4096
> display block size: 1024        # for partition display only
>
> 16 partitions:
> #          size     offset    fstype   fsuuid
>  a:     786432          0    4.2BSD    #     768.000MB
>  b:    8388608     786432      swap    #    8192.000MB
>  d:  303392600    9175040    HAMMER    #  296281.836MB
>  a-stor_uuid: eb1c8aac-d2af-11df-b588-01138fad54f5
>  b-stor_uuid: eb1c8aec-d2af-11df-b588-01138fad54f5
>  d-stor_uuid: eb1c8b21-d2af-11df-b588-01138fad54f5
>
> The slice 1 has 3 partions
>
> a - for /boot
> b - for swap
>
> c- is usually for the whole hard disk in BSDs but it is not shown here
>
> d - the hammer File system labelled ROOT
>
> Just like when you create a volume group in LVM you give it a name
> "vg0" etc when you create a hammer file system you give it a label,
> here the Installed labelled it as "ROOT" and mounted it as
>
>
> ROOT                      288G    12G   276G     4%    /
>
> Now a PFS is a Pseudo hammer File System inside a hammer file system.
> The hammer file system in which the PFSes are created is referred to
> as the root file system.
> ( Don't confuse the "root" file system with the Label "ROOT" the label
> can be anything it is just that the installed Labelled it as ROOT
> because it is mounted as / )
>
> Now Inside the ROOT hammer file system you find the installed created
> 7 PFses let us see how they are mounted in fstab
>
> bash-4.1$ cat /etc/fstab
> # Device                Mountpoint      FStype  Options         Dump
>  Pass#
> /dev/serno/9VMBWDM1.s1a         /boot           ufs     rw
>  1       1
> /dev/serno/9VMBWDM1.s1b         none            swap    sw
>  0       0
> /dev/serno/9VMBWDM1.s1d         /               hammer  rw
>  1       1
> /pfs/var                /var            null    rw              0       0
> /pfs/tmp                /tmp            null    rw              0       0
> /pfs/usr                /usr            null    rw              0       0
> /pfs/home               /home           null    rw              0       0
> /pfs/usr.obj    /usr/obj                null    rw              0       0
> /pfs/var.crash  /var/crash              null    rw              0       0
> /pfs/var.tmp    /var/tmp                null    rw              0       0
> proc                    /proc           procfs  rw              0       0
>
>
> The PFses are mounted using a NULL mount because they are also hammer
> filesystems.
> You can read more on null mounts here
>
> http://leaf.dragonflybsd.org/cgi/web-man?command=mount_null&section=ANY
>
> You don't need to specify a Size for the PFSes like you do for Logical
> Volumes inside a Volume Group for LVM.
> All the Free space in the mother file system is available for all the
> PFses to grow.
> That is the reason in the df output above you saw free space is same
> for all PFses and the root hammer filesystem :-)
>
> Now if you look in /var
>
> bash-4.1$ cd /var/
> bash-4.1$ ls
> account         backups         caps            cron            empty
>         isos            log             msgs            run
>  spool           yp
> at              cache           crash           db              games
>         lib             mail            preserve        rwho
>  tmp
>
> you will find the above directories.
>
> If you look at the status of one of the pfses say /usr you will see
> /var/hammer is the default snapshot directory.
>
> bash-4.1$ hammer pfs-status /usr/
> /usr/   PFS #3 {
>    sync-beg-tid=0x0000000000000001
>    sync-end-tid=0x0000000117ac6270
>    shared-uuid=f33e318e-d2af-11df-b588-01138fad54f5
>    unique-uuid=f33e31cb-d2af-11df-b588-01138fad54f5
>    label=""
>    prune-min=00:00:00
>    operating as a MASTER
>    snapshots directory defaults to /var/hammer/<pfs>
> }
>
> But there is no "hammer" directory in /var now.
>
> That is because no snapshots are yet taken.
>
> You can verify this by checking the snapshots available for /usr
>
> bash-4.1$ hammer snapls /usr
> Snapshots on /usr       PFS #3
> Transaction ID          Timestamp               Note
> bash-4.1$
>
> The best way to tak a snapshot is to run the command 'hammer cleanup'
> it does a lot of things but the fist thing it does is to take the
> snapshots of all mounted pfses. Let us try that :-)
>
> bash-4.1$ sudo hammer cleanup
> cleanup /                    - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/root
>  handle PFS #0 using /var/hammer/root
>           snapshots - run
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /var                 - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/var
>  handle PFS #1 using /var/hammer/var
>           snapshots - run
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /tmp                 - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/tmp
>  handle PFS #2 using /var/hammer/tmp
>           snapshots - disabled
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /usr                 - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/usr
>  handle PFS #3 using /var/hammer/usr
>           snapshots - run
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /home                - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/home
>  handle PFS #4 using /var/hammer/home
>           snapshots - run
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /usr/obj             - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/usr/obj
>  handle PFS #5 using /var/hammer/usr/obj
>           snapshots - disabled
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /var/crash           - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/var/crash
>  handle PFS #6 using /var/hammer/var/crash
>           snapshots - run
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /var/tmp             - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/var/tmp
>  handle PFS #7 using /var/hammer/var/tmp
>           snapshots - disabled
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> cleanup /var/isos            - HAMMER UPGRADE: Creating snapshots
>        Creating snapshots in /var/hammer/var/isos
>  handle PFS #8 using /var/hammer/var/isos
>           snapshots - run
>               prune - run
>           rebalance - run..
>             reblock - run....
>              recopy - run....
> bash-4.1$
>
> You  must have noticed that snapshots were not taken for /tmp /usr/obj
> and /var/tmp.
> That is how it is automatically configured.
>
> Let us look in /var now
>
> bash-4.1$ ls
> account         backups         caps            cron            empty
>         hammer          lib             mail            preserve
>  rwho            tmp
> at              cache           crash           db              games
>         isos            log             msgs            run
>  spool           yp
>
> We have a new directory called "hammer" with the following subdirectories
>
> bash-4.1$ cd hammer/
> bash-4.1$ ls -l
> total 0
> drwxr-xr-x  1 root  wheel  0 Oct 13 11:51 home
> drwxr-xr-x  1 root  wheel  0 Oct 13 11:42 root
> drwxr-xr-x  1 root  wheel  0 Oct 13 11:43 tmp
> drwxr-xr-x  1 root  wheel  0 Oct 13 11:51 usr
> drwxr-xr-x  1 root  wheel  0 Oct 13 11:54 var
>
> Well let us look inside /var/hammer/usr since we are behind /usr ;-)
>
> bash-4.1$ cd usr/
> bash-4.1$ ls -l
> total 0
> drwxr-xr-x  1 root  wheel   0 Oct 13 11:54 obj
> lrwxr-xr-x  1 root  wheel  25 Oct 13 11:43 snap-20101013-1143 ->
> /usr/@@0x0000000117ac6cb0
>
> Ok we have a symlink pointing to some thing let us see what that is
>
> bash-4.1$ hammer snapls /usr
> Snapshots on /usr       PFS #3
> Transaction ID          Timestamp               Note
> 0x0000000117ac6cb0      2010-10-13 11:43:04 IST -
> bash-4.1$
>
> oh yes it is the snapshot that is availablr for /usr.
>
> I guess this gave you some idea.
>
> You can read more about snapshots, prune, reblance,reblock,recopy etc from
>
> http://leaf.dragonflybsd.org/cgi/web-man?command=hammer&section=ANY
>
> especially look under the heading
>
>   cleanup [filesystem ...]
>
> For mirroring I wrote this some time back
>
>
> http://www.dragonflybsd.org/docs/how_to_implement_hammer_pseudo_file_system__40___pfs___41___slave_mirroring_from_pfs_master/
>
> hope this helps to satisfy your curiosity for now :-)
> let me know if you have questions
>
> --Siju
> _______________________________________________
> bsd-india mailing list
> [email protected]
> http://www.bsd-india.org/mailman/listinfo/bsd-india
>



-- 
Regards

Basil Kurian
http://twitter.com/BasilKurian

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