I am making the assumption that you are backing up to the DD appliance with it mounted as an NFS share or possible as a VTL, either way it’s unimportant as the answer is the same.
Data Domain uses what is known as target deduplication, that means that dedupe is done on the appliance, therefore every time RMAN does a backup it sends the complete data set to the appliance. The appliance does an inline dedupe and stores only unique data.
When looking from the OS side you will see pretty much the same amount of data backed up every time. However if you look from the Data Domain side you will see total amount of data written (cumulative figure of OS backups) and amount of data stored will reflect the reduced number you are looking for.
These papers will help explain this, go straight to the results section for a quick example.
For reference EMC Avamar uses what's known as source deduplication, and yes you've guessed it the dedupe is done locally and only the unique data is sent across the transport to the appliance.
DDBoost is also an option, using distributed deduplication, this is a combination of both. The heavy lifting is still done on the DD appliance but the storage node is aware of the unique data on the appliance and only sends the required data to the appliance for further dedupe.
Either way the GUI or CLI will show you what you need.
i assume you are not using DD Boost ? If you are not , you still need to send that RMAN data to DD but as it gets to DD it gets deduped inline. So now if you ssh to DD and run this command against the directory where you sent your data, it should give a rough estimate of deduplication
Dynamox and Dave O: Thank you both for the answers - you confirmed what I was wondering it is simply was a matter that I was not familiar with the device. Now all I have to get someone to agree to is a loggin into it. Thank you again.
houndfish
53 Posts
2
November 28th, 2012 13:00
Hi Dmflinn,
I am making the assumption that you are backing up to the DD appliance with it mounted as an NFS share or possible as a VTL, either way it’s unimportant as the answer is the same.
Data Domain uses what is known as target deduplication, that means that dedupe is done on the appliance, therefore every time RMAN does a backup it sends the complete data set to the appliance. The appliance does an inline dedupe and stores only unique data.
When looking from the OS side you will see pretty much the same amount of data backed up every time. However if you look from the Data Domain side you will see total amount of data written (cumulative figure of OS backups) and amount of data stored will reflect the reduced number you are looking for.
These papers will help explain this, go straight to the results section for a quick example.
Data Warehouse
http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/h8028-backup-recovery-oracle-wp.pdf
OLTP over Fibre Channel
http://powerlink.emc.com/km/live1/en_US/Offering_Basics/White_Paper/h6835-backup-recovery-oracle-clariion-data-domain-ra.pdf
OLTP over NFS
http://powerlink.emc.com/km/live1/en_US/Offering_Basics/White_Paper/h7087-backup-recovery-oracle-clariion-dd-networker-ra.pdf
For reference EMC Avamar uses what's known as source deduplication, and yes you've guessed it the dedupe is done locally and only the unique data is sent across the transport to the appliance.
DDBoost is also an option, using distributed deduplication, this is a combination of both. The heavy lifting is still done on the DD appliance but the storage node is aware of the unique data on the appliance and only sends the required data to the appliance for further dedupe.
Either way the GUI or CLI will show you what you need.
Hope this helps, Dave O’…
dynamox
9 Legend
•
20.4K Posts
1
November 28th, 2012 13:00
i assume you are not using DD Boost ? If you are not , you still need to send that RMAN data to DD but as it gets to DD it gets deduped inline. So now if you ssh to DD and run this command against the directory where you sent your data, it should give a rough estimate of deduplication
filesys show compression /backup/
dmflinn
1 Rookie
•
9 Posts
0
November 29th, 2012 13:00
Dynamox and Dave O: Thank you both for the answers - you confirmed what I was wondering it is simply was a matter that I was not familiar with the device. Now all I have to get someone to agree to is a loggin into it. Thank you again.