Celerra NS-960 10g throughput problem

Our customer have problems with linear read-write to celerra using cifs protocol.

Configuration:

6x15 2T ATA disks

3 FC loops

Created 8x14 RAID5 groups

In celerra all this raid groups populated into default pool.

From this pool we create 1x16TB fs (celerra limit) and presented to cifs server.

We also create lagg using 2x10g ethernet devices, then connect it to cisco nexus.

For test we used HP DL380G7 with 2 port 10g adapter with only 1 active connection. For temp storage we used same Clariion with 14x400gb raid5 FC disks on another backend loop and 8g FC card.

We try to put 300gb file to celerra and then read it...

Average read speed was 180-220mb/s

Write 160-200mb/s

Celerra reported about 15-20% cpu usage.

System has 8g link to AUX. There is speed? How we can find whats the problem? We need expected 600-800+ mb/s in linear r/w... Or 220mb/s is normal for NS-960?

On next week we plan to test same config using NFS...