The read speeds are obtained from an average of all of the duplications that
have been done over a 48 hour period. If I go back 1 week, it turns out to
be something like 80MB/sec average with peaks of 150MB/sec.
We are going to do some direct-to-tape performance testing, but it could
very well be that we just can't pump data out to the drives fast enough to
keep them spinning with a single-stream.
--stuart
-----Original Message-----
From: Peter DrakeUnderkoffler [mailto:pcd at xinupro.com]
Sent: Tuesday, September 19, 2006 10:09 AM
To: Liddle, Stuart
Cc: Paul Keating; veritas-bu at mailman.eng.auburn.edu
Subject: Re: [Veritas-bu] LTO3 throughput on Vault/Duplication jobs
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You then need to test each component individually if you don't know
where your bottleneck lives. There are many ways to test tape drive
throughput
from a media server. Simple dd or tar commands and all the way up to
bpbkar.
When you quote your read speeds of 130mb/sec, is that during a restore
process through netbackup? If so and there is multiplexing, make sure
your restore test is big enough to get a valid sample size.
Thanks
Peter
Peter DrakeUnderkoffler
Xinupro, LLC
617-834-2352
Liddle, Stuart wrote:
> I think we are licensed per TB on the VTL?.not per drive.
>
>
>
> Our rationale in doing the multiplexing to the VTL was to increase
> throughput to the VTL for backups. We CAN increase the number of
> virtual drives instead and then do single streams to the VTL and avoid
> the de-multiplexing during the duplication step.
>
>
>
> However, we are seeing lightning-fast read speeds off of the VTL
> regardless of the fact that it is multiplexed (around 130MB/sec).
>
>
>
> So, I?m still concerned about the speed with which we write out to the
> physical tapes?..not sure where the bottleneck is?but there definitely
> is a bottleneck.
>
>
>
> ------------------------------------------------------------------------
>
> *From:* veritas-bu-bounces at mailman.eng.auburn.edu
> [mailto:veritas-bu-bounces at mailman.eng.auburn.edu] *On Behalf Of *Paul
> Keating
> *Sent:* Tuesday, September 19, 2006 8:49 AM
> *To:* veritas-bu at mailman.eng.auburn.edu
> *Subject:* Re: [Veritas-bu] LTO3 throughput on Vault/Duplication jobs
>
>
>
> My thought's exactly JR.
>
>
>
> I'm thinking folks either have VTLs where they are licensing from the
> vendor on a "per virtual drive" basis, OR, they are licensing Netbackup
> on a (old) per drive, rather than (new) per TB of usable disk basis, so
> want to avoid the licensing cost of adding more virtual drives......that
> was on of my primary criteria in selecting a VTL....I want to be able to
> create as many virtual drives as I want.
>
>
>
> I currently have 20 physical drives, and run various multiplex levels
> for different STUs, depending on the type of backup, in order to
> maintain sufficient data flow to stream the drives, but when the VTL
> comes into play, I want MPX=1, so I'll be configuring upwards of 20
> virtual drives per media server.
>
>
>
> Paul
>
>
>
>
>
> --
>
> -----Original Message-----
> *From:* Dyck, Jonathan [mailto:Jonathan.Dyck at cognos.com]
> *Sent:* September 19, 2006 10:09 AM
> *To:* Paul Keating; Liddle, Stuart; veritas-bu at mailman.eng.auburn.edu
> *Subject:* RE: [Veritas-bu] LTO3 throughput on Vault/Duplication jobs
>
> Agreed. Coming from an environment where we are "afraid" of
> multiplexing everything due to those image's importability (or lack
> thereof), the fact that we cannot demux quick enough has us
> handcuffed a little.
>
>
>
> Just a question, what's the rationale on mpx'ing to your VTL's?
>
>
>
> Cheers,
>
> Jon
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Veritas-bu maillist - Veritas-bu at mailman.eng.auburn.edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
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