NO....Don't use Vault to duplicate from VTL to physical tape!!!

We tried this, and in NB 5.1 MP6, Vault is a HOG!!  We were not able to keep
the drives spinning fast enough using Vault.  The best speeds we saw going
to physical tape using vault was maybe 30MB/sec.  Usually we got around
10MB/sec or less....which is definitely not a good thing.

What we ended up doing was using the built-in feature of our NetApp VTL to
do the cloning of the virtual tape to physical tape.  Now we are getting
much better performance of around 50 - 60 MB/sec.

The problem is that Vault has way too much overhead in doing the copying of
the data.  It's kind of like this:

-- you have one firehose coming in (data from the VTL)
-- you have another firehose going out (data to the physical tape drive)
-- then you have to empty the incoming firehose into a bucket and look at it
and then pour that bucket into the other hose going out.

With the built in cloning function of the VTL, you just connect the two
firehoses together and the data gets written from virtual tape to physical
tape.

--stuart (backing up over 200TB per week to VTL) liddle

-----Original Message-----
From: veritas-bu-bounces at mailman.eng.auburn.edu
[mailto:veritas-bu-bounces at mailman.eng.auburn.edu] On Behalf Of Blaine
Robison
Sent: Friday, May 11, 2007 8:05 AM
To: VERITAS-BU at mailman.eng.auburn.edu
Subject: Re: [Veritas-bu] Newbie to Netbackup using VTL

I understand that VTL able to create multiple tape libraries and tape
drives.

Yes this is correct. There is a limit depending on the manufacturer.

> If i'm cloning data that already backup in VTL to the actual tape library,
> what is the common practice? script? netbackup? 

Common practice is to use vault.
You can create a script using bpduplicate.

> Let's say if i have 100 clients and i do not use multiplexing and instead
> creating 100 virtual tape drives, does it mean that i need 100 LTO3 tape
when
> i do cloning? Will the activity monitor display backup failure from VTL to
> the normal tape library?

If you are limiting retentions to 1 retention per tape and you have 100
retention periods then yes.

If you have only 10 retention periods, you will utilize your tapes more
efficiently when you clone. 

Yes, It will look just like a tape library to tape Library duplicate
failure.

--- dy018 <netbackup-forum at backupcentral.com> wrote:

> 
> Hi everyone,
> 
> I'm new using VTL with netbackup.
> 
> I was hoping anyone here already implemented such a setup in their current
> environment and hope share your general setup plan? I'm now planing for
such
> a setup and only have experience using normal tape libraries.
> 
> I understand that VTL able to create multiple tape libraries and tape
drives.
> If i'm cloning data that already backup in VTL to the actual tape library,
> what is the common practice? script? netbackup? 
> 
> Let's say if i have 100 clients and i do not use multiplexing and instead
> creating 100 virtual tape drives, does it mean that i need 100 LTO3 tape
when
> i do cloning? Will the activity monitor display backup failure from VTL to
> the normal tape library?
> 
> Any help is much appreciated. Thank you in advance
> 
> 
> 
> 
> 
> _______________________________________________
> Veritas-bu maillist  -  Veritas-bu at mailman.eng.auburn.edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
> 


Blaine Robison
Solaris Ceritfied System Administrator 
Solaris Certified Network Administrator
Veritas Certified Professional
972-853-2459
214-578-5391


       
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