The "logical error" question has come up before.  With no TSM managed copy
pool you are perhaps at a slightly higher risk.

An option is to still have a copy pool, but on the same DD.  So little real
disk usage, but some protection from a TSM logical error.  That obviously
does not protect you from a DD induced one.

FWIW, when we implement VTL's, and if the bandwidth allows, we use TSM to
create the copy.  Small sites with limited bandwidth, we rely on the
appliance.

Steven



On 4 October 2011 06:41, Daniel Sparrman <daniel.sparrman AT exist DOT se> 
wrote:

> > If someone puts a high-caliber bullet through my Gainesville DD, then
> > I recover it from the replicated offsite DD, perhaps selecting a
> snapshot.
> >
> > If someone puts a high-caliber bullet through both of them, then I
> > have lost my backups of a bunch of important databases.
>
> And if you have a logical error on your primary box, which is then
> replicated to your 2nd box? Or even worse, a hash conflict?
>
> I dont consider someone putting a bullet through both the boxes a high
> risk, I do however consider other errors to be more of a high risk.
>
> Best Regards
>
> Daniel
>
>
>
>
>
> Daniel Sparrman
> Exist i Stockholm AB
> Växel: 08-754 98 00
> Fax: 08-754 97 30
> daniel.sparrman AT exist DOT se
> http://www.existgruppen.se
> Posthusgatan 1 761 30 NORRTÄLJE
>
>
> -----"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> skrev: -----
> Till: ADSM-L AT VM.MARIST DOT EDU
> Från: "Allen S. Rout"
> Sänt av: "ADSM: Dist Stor Manager"
> Datum: 10/03/2011 23:38
> Ärende: Re: [ADSM-L] Ang: Re: [ADSM-L] Ang: Re: [ADSM-L] Ang: Re: [ADSM-L]
> vtl versus file systems for pirmary pool
>
> On 09/28/2011 02:16 AM, Daniel Sparrman wrote:
>
> > In this mail, it really sounds like you're using your DD as both
> > primary storage and for TSM storage.
>
> I am, right now, using the DD as a target for direct-written database
> backups, only.  So that's not really "primary storage", as I think
> about it.
>
>
> > If the DD box fails, what are your losses?
>
> If someone puts a high-caliber bullet through my Gainesville DD, then
> I recover it from the replicated offsite DD, perhaps selecting a snapshot.
>
> If someone puts a high-caliber bullet through both of them, then I
> have lost my backups of a bunch of important databases.
>
>
>
> > Sorry for all the questions, I'm just trying to get an idea how
> > you're using this box.
>
> No problem. Our conversation is fuzzed by the fact that I am also
> talking about how one _might_ use it for TSM storage.  I'm
> contemplating it, but not doing it at the moment.
>
> > [ ... if you lose a DD, then ... ] you have to restore the data from
> > somewhere else (tape?).
>
>
> In my planning, the DD gets copied / offsited to a remote DD, so
> that's the somewhere else.
>
> - Allen S. Rout
>