Single Instance Service

Jeff Mohler speedtoys.racing at gmail.com
Thu Apr 26 16:53:34 UTC 2007


It can if your storage appliance supports ASIS.  Some even operate at the
block level, not just the file level.

On 4/26/07, GARRISON, TRAVIS J. <garrisot at otc.edu> wrote:
>
> > -----Original Message-----
> > From: owner-freebsd-questions at freebsd.org [mailto:owner-freebsd-
> > questions at freebsd.org] On Behalf Of Olivier Nicole
> > Sent: Thursday, April 26, 2007 1:36 AM
> > To: m.seaman at infracaninophile.co.uk
> > Cc: GARRISON, TRAVIS J.; freebsd-questions at freebsd.org
> > Subject: Re: Single Instance Service
> >
> > > Sure it is.  You will need to write a small shell script to scan
> > > your disk volume and calculate the checksum of each file.  When
> > > ever it finds a duplicated checksum, then it copies the file into
> > > the central store and replaces the on-disk copies with symbolic
> > > links.  That's fairly trivial to write.
> >
> > Beside, what should be the behaviour when one wishes to modify his own
> > copy of a document? How does Single Instance acts in that case?
> >
> > If you establish a link, there is only one version of the file, once
> > and forever (unless you go and unlink it manually), so when one
> > modifies the file, modification applies for everyone.
> >
> > Olivier
> [GARRISON, TRAVIS J.]
>
> I know with Windows Storage Server, if a user modifies the file, it will
> then create the user their own copy of the file. This happens
> automatically. Exchange Server is another example of this type of
> storage. When someone sends an attachment to several people, the server
> saved one copy of the file. I am currently managing 7TB worth of data
> with roughly 1 to 2TB of duplicate files. This gets fairly expensive
> with a fiber channel san backend. I know it can be done in the windows
> world automatically, just wondered if it could be done automatically in
> the Unix world also.
> _______________________________________________
> freebsd-questions at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to "
> freebsd-questions-unsubscribe at freebsd.org"
>


More information about the freebsd-questions mailing list