SLP from VTL to VTL - Optimize Duplication?

[Jeffrey_WQX]

Hi,

I have a question regarding SLP and optimize duplication.I have 2 VTL's located in 2 different location under the same NetBackup domain. The VTL is actually create on a HP StoreOnce device which has deduplication & replication capability. In this case when SLP is triggered, the duplication traffic will it be via the media servers? Or it will be only between the 2 VTL?

In what scenario where Optimize Duplication be possible in my case?

Regards,

Jeffrey

[RiaanBadenhorst · Accepted solution]

Hi,

The storeonce has optimized duplication if used as an OST device, but not when used as VTL.

http://www.symantec.com/business/support/library/BUSINESS/xCL/TECH76495/nbu_7x_hcl.html#ost_secondary_storage_solutions-ost_storage_servers-ost_storage_servers_-_vendor_compatibility-hp

This is because when you write to a VTL, NetBackup thinks its a tape, so it will treat it as a tape. Duplications will read and write the entire image via the media servers.

[Marianne]

I agree with Riaan. 

Optimized duplication is for dedupe disk storage units only.

I often wonder why people are still using VTL. The technology is so 'last century ' when backup application could not effectively use disk.

[VoropaevPavel]

Note that D2D StoreOnce OST license called catalyst and requires addition purchase.

[Nicolai]

This is one one of the reasons why tape sucks (both phycial and virtual).

Options for duplication and replication is much extensive using disk as backup medium (not limited to MSDP, OnceStore, Data Domain etc etc).

[Nas_lGidiyor]

I guess money talk.... between VTL and Pure Disk Units.

[Nicolai]

VTL is quite expensive as well. A VTL license for a OST enabled device cost easily 30.000 USD

[sdo]

I think VTL has it's uses.  Especially if it compresses.

A good VTL can usually be used as a FC target - whereas a typical de-dupe server or appliance is LAN based.

SAN FC = guaranteed packet delivery - can be designed non-blocking, and use cut-through routing :)

LAN TCP = no guarantee of delivery of packets - typically always shared infrastructure, and usually has a degree of contention ratio.

A good VTL will let you pre-carve the entire storage back-end in to fixed quantity of fixed size virtual tapes - which should result in a genuine smooth IO profile across all of the parity group stripes over the back-end disks.

Virtual tape drives can be multi-plexed - and SLP's can be configured to preseve multi-plexing for duplication to tape.  Genuinely fast disk to fast tape.

If you don't implement de-dupe within the VTL then you don't have to worry about re-hydration performance.

I think there are use cases for VTL such as when you need very fast data target staging area for large volumes of data, and you can live with a short retention period on that first SLP stage.

[Jeffrey_WQX]

Hi Riaan,

Thank you for the clarification. Actually i am trying to avoid huge amount of data moving across network during duplication. So I guess the best way now is to ditch VTL setup and go ahead with OST disk based backups.

Now on to purchase the Catalyst license from HP and a Enterprise Disk from Symantec for the OST functionality.

[Jeffrey_WQX]

Thank you all for the valuable inputs. After considering all and my requirements is to reduce bandwidth utilization during duplication across WAN, best way now is to moved towards OST implementation. 

1st thing to do now is get the licenses to get OST working.