sounds strange

I would first verify that the network is indeed good.

one simple way to do that is using ftp - a simple protocol that you can also compare the results between Windows and Unix.

If you already have CIFS configured you should be able to just ftp to the data mover using user.domain as the login name and the CIFS password
If not just create a local test user with /nas/sbin/server_user server_2 -add -passwd

If your ftp read performance differs vastly from the write performance you do have a network problem.

then you can see if there maybe is a performance difference between the WIndows and the Unix file systems.

I suggest to open a case with support then

The network seems to be clean.

Unix performances are 12 x greater than CIFS performances.

For CIFS
I have used two differents windows hosts to compare the cifs r/w perf, that are the sames.

A case is opened.

But no response

Response times are related to severity. You'll get a response, don't worry.

The first thing I would check is that the speed of the IP port indeed does match the port speed of the switch/router. Way too many times the auto/auto setting results in the host getting a random configuration like 100 simplex while the port thinks it 1000 duplex. This can result in (believe it or not) the ability to ping and send small files but real slow transfer of larger files. We've just standardized on using fixed speeds wherever we can, usually the switches allow this, and only use auto on the hosts when we can't fix the speed.

Forget science, make it work!

What kind of switches do you have?
Are you using IP Telephony?

Yes, TOIP is implemented on the network.

I think there was a problem with some Cisco switches / modules and the QoS normally setup for Telephony

It should affect NFS as well though - at least you should see retransmits

Hi,

We were also having performance bottleneck while reading data from Celerra. After some investigation and consultation with EMC, we have changed fastRTO setting on data-movers from default value of "0" to "2" and now getting almost full throughput. Before this change we were getting very low throughput (<10Mbps) while reading from any Celerra machine.

In our scenario, Celerra is connected to 3Com Core Switch 8810 via aggregated links of 2x1Gbps and clients are connected through edge switch on 100Mbps ports. Now clients are getting 90 to 100 Mbps.

Can you share your fastRTO current settings?

Regards,

Saleem