10 GbE performance troubleshooting 1

On a Windows 2003 server with 1 GbE NIC and DSN writing to DataDomain device, I can see about 140 MB/s (dedup happens on the DSN and NIC utilization is approx 15%).

Now, with 2 Windows 2008 R2 servers setup with 10GbE, I copy a file from one Windows 2008 R2 to another one.  It at most utilizes 12% of the 10GbE.  If I add write another file at the same time, I see the utilizes 20% of the 10 GbE.  I follow some of the suggestions by Cisco to tweat the OS (only thing I have not done is Jumbo frame).  However, I don't see much improvement.

After doing more research, it looks like it is an OS limitation.  See kb article from HP site.

"There was still perceived TCP performance issue, but it turned out to be a matter of limitations in performance per thread in Windows Server 2003. For instance, if copying only one file from one server hosting a NC522SFP to another using a NC522SFP, only a small fraction of the theoretical 10-Gigabit performance was achieved. However, if multiple sessions were run simultaneously, similar performance gains were seen as with UDP. In other words, the bottleneck was not the NIC."

Hopefully, I will have more time to run test and determine the limitation in the summer.  Not sure if Linux / Unix will do a better job.

DataDomain support with NetWorker 7.6.2 and 7.6.3

With NW 7.6.2 boost devices, max session supported / devices are increased.  Max default session / device will be 10 instead of 4 in NW 7.6.1.  Dedup ratio will not be affected since it is SN side dedup for boost device.  I remember if AFTD is used, set the max session to 1 per device in 7.6. 

With NW 7.6.3, multiplexing is supported for VTL in DataDomain. 

Keep in mind as mentioned in the older article, NW 7.6.3 does not support DDOS 4.9.  If you plan to upgrade from NetWorker 7.6.1 to 7.6.2, make sure you go through the DataDomain Integration guide for NetWorker 7.6.2.  My plan is to stage off the saveset from old DD devices after migration to the new one generated in NW 7.6.2.  This seems to be the simplest option. 

Once migration completed, a case will be open with DataDomain to remove the old unused LSU.  You cannot delete old LSU from NetWorker / DataDomain GUI.  Do not delete LSU that contain data.