I'm not fully aware of how the DD replicates data, but if you have 15-20TB/day 
being written to your main DD, and that data is then replicated to the off-site 
DD, how much data is actually replicated?
 
With a 1Gbs connection, you could hit values up to 360GB/s hour (expecting 
100MB/s which should be theoretically possible, but it's usually lower than 
that on a 1Gbs connections) which means 8.6TB per 24 hours. So the data is both 
deduplicated and compressed before you send it offsite?
 
Does the DD do the dedup within the same box, or require a separate box for 
dedup?
 
You're also running with the same risk as the previous poster, you're relying 
entirely on the fact that your DD setup wont break. Is this how the DD is sold? 
(Buy 2 DD's, replicate between them and you're safe) ? I know it's (like the 
previous poster stated) always a question about costs vs mitigating risks, but 
if I got to choose, I'd rather have fast restores from my main site and slow 
from my offsite, as long as I can restore the data. Instead of having fast from 
main, fast from off, but there's a chance I might not be able to do restore at 
all.

If DD claims they have "data invunerability" I'd really like to see how they 
hit 100% protection, since it would be the first system in the world to 
actually have managed to secure that last 0,0001% risk ;) RAID usually was 
"secure" until someone made an error, put in a blank disk and forgot to rebuild 
:)
 
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: Shawn Drew <shawn.drew AT AMERICAS.BNPPARIBAS DOT COM>
Sänt av: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
Datum: 09/28/2011 22:26
Ärende: Re: [ADSM-L] Ang: Re: [ADSM-L] Ang: Re: [ADSM-L] vtl versus file 
systems for pirmary pool

We average between 15-20TB/day at our main site, and that goes directly to 
a single DD890 (no random pool) .  single-pool, file devclass, NFS mounted 
on 2x10GB crossover connections. Replicates over a 1gb WAN link to another 
DD890.   (I spent all the money on the DD boxes, I didn't have enough left 
over for 10GB switches!)

That other DD890 backs up another 7-10TB/day, replicating to the main site 
   (bi-directional replication). 

All with file devclasses and there is not more than a one hour lag in 
replication by the time I show up in the morning.    TSM doesn't have to 
do replication or backup stgpools anymore, so I can actually afford to do 
full db backups every day now.  (I was doing an incremental scheme before)

IBM has a similar "recommended" configuration with their Protectier 
solution, so they do support a single pool, backend replication solution.  
Data Domain also claims that "data invulnerability" which should catch any 
data corruption issue as soon as the data is written, and not later, when 
you try and restore. 


Regards, 
Shawn
________________________________________________
Shawn Drew





Internet
daniel.sparrman AT EXIST DOT SE

Sent by: ADSM-L AT VM.MARIST DOT EDU
09/28/2011 02:13 AM
Please respond to
ADSM-L AT VM.MARIST DOT EDU


To
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Subject
[ADSM-L] Ang: Re: [ADSM-L] Ang: Re: [ADSM-L] vtl versus file systems for 
pirmary pool






How many TB of data is common in this configuration? In a large 
environment, where databases are 5-10TB each and you have a demand to 
backup 5-10-15-20TB of data each night, this would require you to have 
10Gbs for every host, something that would also cost a penny. Especially 
since the DD needs to be configured to have the throughput to write all 
those TB within a limited amount of time.
 
Does the DD do de-dup within the same box (meaning, can I have 1 box that 
handles normal storage and does de-dup) or do I need a 2nd box?
 
And the same issue also arises with the filepool, you're moving alot of 
data around completely unnecessary every day when u do reclaim. 
 
If I'm right, it also sounds like (in your description from the previous 
mails) you're not only using the DD for TSM storage. That sounds like 
putting all the eggs in the same basket.
 
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" <asr AT UFL DOT EDU>
Sänt av: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
Datum: 09/27/2011 18:55
Ärende: Re: [ADSM-L] Ang: Re: [ADSM-L] vtl versus file systems for pirmary 
pool

On 09/27/2011 12:02 PM, Rick Adamson wrote:


> The bigger question I have is since the file based storage is
 > native to TSM why exactly is using a file based storage
 > not supported?

Not supported by what?

If you've got a DD, then the simplest way to connect it to TSM is via
files.  Some backup apps require something that looks like a library, in
which case you'd be buying the VTL license.

FWIW, if you're already in DD space, you're paying a pretty penny.  The
VTL license isn't chicken feed, I agree, but it's not a major component
of the total cost.


- Allen S. Rout


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