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Nabeel124
1 Nickel

Write speed on Tape Library is 10MB/s

Hi All,

I have configured Networker with Data Domain for backups via DDBoost over IP and then cloning from Data Domain to Physical Tape Library is configured. Tape Library have two 8Gbps drives and LTO-6 tapes are used. During cloning Job write speed on tape is too slow i.e 10MB/s. Proper zoning is configured between Networker Server, Data Domain and Tape Library. Please anyone can help me in this or provide me steps to verify the configuration.

Regards

Nabeel Ahmed

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8 Replies
ledugarte
2 Iron

Re: Write speed on Tape Library is 10MB/s

I suppose your networker server is the only storage node. If so, your data is being backed up to Data Domain deduplicated. And then, when you are clonning to tape, data is inflated, send to networker server via IP and then, go to tape via FC. Your bottleneck is not FC, I think your bottleneck is IP network or resources in Networker Server.

Take a look into Network, CPU and RAM when clonning is running.

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bingo.1
4 Tellurium

Re: Write speed on Tape Library is 10MB/s

This is possible. However, one cannot be precise without further looking at your environment.

If the network is not the bottleneck, these are the 2 worst case scenarios:

  - You have a bunch of small save sets and the tape must reposition pretty often. (the source is to slow)

  - You have setup your clone jobs in a way that the data cannot be sent fast enough the keep both drives streaming.

In general it is a combination of those and other factors, of course.

May I suggest that you use one disk volume first and clone its save sets to tape. This way you might achieve a better throughput for your tape drive. If this works fine, go ahead and add another clone job for the next volume etc.

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princeaijaz
1 Nickel

Re: Write speed on Tape Library is 10MB/s

You might also check tape drive drivers. if IBM drives you will need IBM

drivers only and install them in non-exclusive mode.​

On Mon, Nov 27, 2017 at 6:30 PM, bingo <emc-community-network@emc.com>

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Nabeel124
1 Nickel

Re: Write speed on Tape Library is 10MB/s

Yes Networker server is the only storage node. I have configured zoning between Networker Server, Data Domain and Tape Library. As NW server HBA is of 4Gbps, when clone job start soon after backup job finishes i can see that DD pool or device go in to reading mood from write and at that time speed from DD is shown 400 MBps but on tape drive it is showing write speed at 10MBps as time passes speed start reducing from 400 MBps to 15 - 20 MBps.
Networker server has 12 GB of RAM and 3.2 GHz of processor.

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Nabeel124
1 Nickel

Re: Write speed on Tape Library is 10MB/s

Thanks for reply.

I have have done like same like that first backup job runs and when it is finished then clone job starts.
I have tested separately to clone some savesets to Tapes but problem still persists.

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Nabeel124
1 Nickel

Re: Write speed on Tape Library is 10MB/s

Hi have installed proper IBM drivers.

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ledugarte
2 Iron

Re: Write speed on Tape Library is 10MB/s

Have u tried with backup direct to tape?. How is the performance if you send data directly to tape.

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Nabeel124
1 Nickel

Re: Write speed on Tape Library is 10MB/s

Yes i have tried with backup direct to tape.  Same write speed of 10MB/s.
Please suggest what can i do for this?

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