Our performance model goes up to 2TB/hour which is a little shy of what
you are getting - 600MB/sec.
The cool thing is that model is for both backup to disk (HOST to VTL)
and disk to tape (VTL to Physical Tape) as long as you have the tape
drives to support up to 2TB/hr...which in your case wouldn't be an issue
:-). Since we synchronize the physical barcode to the virtual barcode
we're able to generate a NetBackup (or TSM) formatted physical media
which is able to be read by any other NetBackup media server.
David A. Chapa | ADIC | 720.272.8452 cell | http://www.adic.com
Sr. Technical Advisor
-----Original Message-----
From: Fred.Bateman AT usdoj DOT gov [mailto:Fred.Bateman AT usdoj DOT gov]
Sent: Thursday, February 17, 2005 4:08 AM
To: David Chapa; 'veritas-bu AT mailman.eng.auburn DOT edu'
Subject: RE: [Veritas-bu] VTL questions
David,
In regards to #3, we run about 600MB/sec to an
IBM 3584 with 12 FC LTO2 drives. This is doing
both backups and restores of multi-terabyte
Oracle databases. We could fairly easily
double or triple this by just adding more
tape drives and FC HBAs. Beyond that would
require more CPU and disk. Can your
VTL really do this?
Fred
P.S. We use TSM for this but I would assume
Netbackup could get similar results.
-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]On Behalf Of
david.chapa AT adic DOT com
Sent: Wednesday, February 09, 2005 5:23 PM
To: Bruce.Chewning AT suntrust DOT com; veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] VTL questions
Importance: Low
Alright...I work for ADIC who has their own VTL. I'll give you my
perspective as unbiased as possible. Many can attest on this list prior
to joining ADIC I've been talking / addressing the value of disk based
backup and VTLs for quite some time.
See my comments inline.
Incidentally you can access the Micro-site for our product at
http://www.adic.com/gopathlightvx
David A. Chapa | ADIC | 720.272.8452 cell | http://www.adic.com
<http://www.adic.com>
Sr. Technical Advisor
Pathlight VX - http://www.adic.com/gopathlightvx
-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu] On Behalf Of
Chewning.Bruce
Sent: Wednesday, February 09, 2005 2:49 PM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] VTL questions
We have been looking at Virtual Tape Libraries and I have a few
questions to ask those who have used them.
1. Should you let the VTL make copies to tape or insist that a media
server write to tape.
If you are facing an exposure issue with getting your backup media
offsite via duplication / vaulting, then you may want to look at letting
the VTL create your media. I say this with one very BIG caveat. You
want to ensure that you #1 have enough bandwidth on the back end of your
Virtual Tape Library to ensure you can create tapes in accordance with
your window for physical tape creation. #2 you want to make sure that
the barcodes in your physical library are synchronized to your virtual
cartridges on the VTL's disk. Automation of the barcode synchronization
is best, manual is okay but requires a higher degree of touch and
management. #3 If you allow the VTL to create your physical tape you
also want to ensure that you are allowed to use the physical tape as a
COPY for DR, in other words allow you to separate the physical from the
virtual. So now you have an online copy still (virtual) and a DR copy
offsite (separated physical).
2. When you selected your VTL, how did you compare them? How did you
size the VTL you chose?
We have a tool our field uses to help size the VTL, however, I would
suggest that you look at how much data you plan on backing up, how many
copies you need online for high speed recovery and how many media are
required (physical) so you can adequately size your "backend" library.
3. Why do some docs say sometimes restoring from tape can be faster than
restoring from the VTL.
I've not heard this one. I would love to read some of those writings.
4. How are you maximizing performance with VTL? What strategies are you
using for large amounts of data.
I've done all of the performance testing for our offering (Pathlight VX)
and ran through performance testing the same way I would have done with
conventional tape (bptm and bpbkar logging). I ended up with 256K block
size (UNIX) and approximately 64 data buffers.
5. Does multiple streams still make sense?
Multiple streams make sense, but multiplexing doesn't necessarily, based
on your LAN / SAN infrastructure. The nice thing about VTLs is you are
able to send data to individual tape drives as fast or as slow as your
servers can afford. However the other side of the coin is you may not
have licenses for ALL of the tape drives necessary to avoid
multiplexing. So at that point it may be for your environment, MPX is
right, but perhaps you can reduce the number of MPX streams. This would
really be a tuning disucsion.
6. What tools are you managing your VTL with?
We have a browser based interface.
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