-- 
> Yeah....there's a way to scan the physical library and the > VTL will create 
> a> set of virtual tapes with the same barcodes as the physical> 
> tapes....NetBackup will basically not know the difference and > will treat> 
> them the same.
Gotcha....Falconstor style.
> > The problem would be if you had not gotten > all of the data> transferred 
> > from the VTL to the physical tapes before the VTL > gets hit with> some 
> > kind of failure.
Exactly....NBU would think the data is on tape but it's not.

> If you are getting 30MB/sec to tape with vault/duplication, > you're lucky.
I'm writing tape to tape, without "demultiplexing", so I'm essentiallywriting a 
whole bunch of 2 gig files (using 2 gig fragments)
> I've found that it is highly dependent upon the image size > and the makeup 
> of> the image itself.  If you have a number of small images, you > will lower 
> the> throughput of vault.  Also, if you have a large image that is > made up 
> of a> number of small files, you will also impact the throughput.  > The best 
> case> is a large image made up of large files.
However, an image fragment is a "big" file...the vault/dupe shouldn't belooking 
at anything smaller than a frag.
> > Think of it this way....it's like having a couple of > fire-hoses for the 
> > data> flow.  One is coming into the media server from the VTL and > the 
> > other is> out-bound to the physical tape drives.  Vault/duplication > does 
> > not allow you> to simply connect the fire-hoses.  It has to empty the > 
> > in-coming one and put> that data into buckets then empty those buckets into 
> > the out-going> fire-hose.  Oh....and while it is filling the buckets, it's 
> > > doing an audit> to ensure that you have the right number (counting the 
> > image > fragments,> etc).  The nearstore VTL will actually connect the 
> > fire-hoses > and you get> line-speeds because it's doing the copy at a 
> > block-level to > the physical> tapes.
Comes down to what matters to you, I suppose. Many of the VTLs on themarket 
will operate like that.Seems all the big analysts as well as Symantec shun the 
idea.
> As for the performance into the VTL, we don't really care, 
I don't mean on a per stream basis....I mean more on a meeting thebackup window 
SLA basis.
Are you getting 1/2 TB/hr? 1 TB/hr?
What about if you have disk->tape dupes running, hitting the disk arraywith a 
buttload of reads? Does it impact your backups?
Paul====================================================================================
La version fran?aise suit le texte anglais.
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