A couple of 5.3 questions

[Matthew Seaman]

On Sat, Nov 13, 2004 at 11:19:18AM -0500, Francisco Reyes wrote:
> Plan to soon move to 5.3 through a backup, fresh install proces..
> 
> One of the main reasons I am moving is for the snapshot capability.
> Reading the man for MKSNAP_FFS(8) I see
> mksnap_ffs mountpoint snapshot_name
> 
> Question: Does mountpoint has to be a filesystem or can it be a directory?
> For example if I have:
> /
> /usr
> /var
> 
> Can I make a snapshot of /usr/home? Or I can only do /usr?
> 
> Then I went on to look at how to mount snapshopts, and although found the 
> info, got a little more confused.
> 
> The mount command has in the man page:
> snapshot
> This option allows a snapshot of the specified
> file system to be taken.
> 
> So is mount or mksnap_ffs that makes the snapshot?
> 
> The only reason I am trying to get this info is to know if to make a 
> separate filesystem for files I would like to snapshot.

The snapshot capability is a filesystem wide thing: ie. you can
snapshot a whole partition, not just small parts of it.  mount(8) will
call mksnap_ffs(8) to create the snapshot -- that's typical of the way
mount is designed.  When you say 'mount -t foo', you actually end up
trying to run a command 'mount_foo' (of which there are about 17
variants available on this 4.10-STABLE system) -- that lets arbitrary
new filesystem types be added to the system very easily.

Once you've made your snapshot, you can do things like backing up just
selected parts of it, no problem.  So long as there aren't massive
changes going on in that partition, the snapshot shouldn't take up too
many system resources.

I think what you want would be a very similar concept: file
versioning.  That's something which is available in eg. Windows
Server, but that hasn't been implemented on FreeBSD -- or, as far as I
know, on any Unixoid system.  

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20041113/47aeade4/attachment.bin