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Mark_RFlag for United Kingdom of Great Britain and Northern Ireland

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DataDomain VTL / NetWorker - best architecture

Hi,

Does anyone have any experience of using EMC DataDomain (DD) units (DD670s especially) as VTLs with EMC NetWorker for their backup solution?  
I'm looking at using the same but have been presented with two potential architectures; the first I have been 'expecting' as it was discussed a while ago, but the second (and latest) has raised some questions and I can't find enough information I need to either back it up (no pun intended!) or dismiss it.

Environment: Two DCs, less than 30km apart with 30Mb link between the two.  DD670s and RP units talk over the link (Production <=> DR).  Predominantly HP-UX systems, some Windows.  EMC VNX SAN.

The first architecture mentioned above involves a top-level NetWorker Server (NS) and two Networker Storage Nodes (NSNs); pretty standard stuff, NS controlling the jobs and dedicated NSNs shifting the data (from the backup clients) to the DDs.  I haven't had detailed sight of the connecitivity but assumed the NSNs were multi-homed, with GbE to a Backup VLAN (for backup client connecitivity) and fibre to a multi-Gbps fabric which also connects the DDs (for throughput).

The second architecture has two main differences; the NSNs role is no longer on dedicated servers, the role moved to each backup 'client', i.e. the app and db servers themselves.  Secondly, the DD670s are both GbE-connected, no fibre connectivity.

This has raised more questions that I could really post here, so my main ones are:
1) Has anyone implemented their solution the second way and did it have any negative effects, e.g. poor server performance, incompletion within backup windows, incompatibilities, etc.
2) Does the DD670 need fibre-connections if used as a VTL? GbE just seems as though it might be more than a little stretched with a large client base/lots of data.  Also, the standard DD config seems to be only two GbE NICs, which would be taken up for other purposes than the dedicated Backup VLAN here.

TIA

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Are you intending to backup between the two sites?

If so your 30Mbps link will be far to slow. @3MBps, say 2MBps in reality it will take you too long to transfer any siginificant amount of data.
no only the DD670 replication goes over the 30 Mbps link as he stated
But even if the dedupe gives you 20:1 reduction it still means that writes to one dd670 of anything over 40MB/s (and even that is optomistic) will be too much.
The dedupe of dd670 is transparent. You always transfer all the backup data to the virtual tape then dd670 handles it. Therefore you need to keep max 8 paralel sessions writing to it and no parallelism on client is recomended so that the dedupe is really working. Dedupe is for space saving not for data transfer/ throughput saving
Guys i think you are missing the point. If you have 2 * DD670 replicating either one-way or to each other over a 30Mbps link the link is going to become a serious bottleneck once the data being transferred reaches the 2MBps threshold, it doesnt matter what the data is or if it is already deduped, the synchronisation of the two boxes will be compromised.
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Cheers for all of the input, folks.....much appreciated!

With regards to the links, if my memory permits I'll update the thread if there are any issues.  The link size has been considered in the design though, which EMC themselves have provided significant input for.