UFS2 Snapshot limitiations

[Pietro Cerutti]

On 3/13/07, Bill Moran <wmoran at potentialtech.com> wrote:
> In response to "Pietro Cerutti" <pietro.cerutti at gmail.com>:
>
> > On 3/13/07, Bill Moran <wmoran at potentialtech.com> wrote:
> > > In response to "Pietro Cerutti" <pietro.cerutti at gmail.com>:
> > >
> > > > On 3/13/07, Doug Poland <doug at polands.org> wrote:
> > > > >
> > > > > On Tue, March 13, 2007 10:10, Bill Moran wrote:
> > > > > > In response to "Doug Poland" <doug at polands.org>:
> > > > > >
> > > > > >> Hello,
> > > > > >>
> > > > > >> I seem to recall, but cannot find, the limitation on the number of
> > > > > >> snapshots allowed on UFS2.  Could someone point me in the right
> > > > > >> direction please?
> > > > > >
> > > > > > The handbook has it:
> > > > > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/snapshots.html
> > > > > >
> > > > > Thank you very much.
> > > > >
> > > >
> > > > Sorry for joining the thread, but it's raised my curiosity: what's the
> > > > reason for this limit?
> > >
> > > I'm not 100% sure, but I believe it's because snapshot information is stored
> > > in the filesystem superblock, and that's all that can fit in the space
> > > available in the superblock.
> >
> > This is the same thing that came to my mind, but in the handbook page I found:
> > "Active snapshots are recorded in the superblock so they are
> > persistent across unmount and remount operations along with system
> > reboots."
> >
> > 1) what an "active" snapshot is?
>
> I think you're trying too hard to read into this.  Active snapshot, as opposed
> to a snapshot that has been deleted/unmounted and existed in the past, is what
> I took it to mean.

Makes sense.

Thanks!

>
> --
> Bill Moran
> http://www.potentialtech.com
>


-- 
Pietro Cerutti

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