785 4 Gpbs HBA just can't seem to put past 2 Gpbs.

[S Petersen]

Greetings,

We have two 785G5's each with 2 x dual port 4 Gpbs HBA's that are attached to 4 Gpbs SAN ports that are attached to 4 Gpbs Storage ports.

For some unknown reason, the max performance is roughly 180 MB/Sec throughput. The storage at both sites (HDS USP V) is very capable of handling the throughput. The server setups are almost identical and are a DR solution. One server is in one Data Centre using 4 Gpbs Brocade 48000 switch ports and the other server is in another Data Centre using 8 Gpbs Cisco MDS ports. The switches and the servers both have 4 Gpbs links.

I cannot fathom why we are not getting at least double the performance. The servers are x64 Windows 2008 Enterprise 24 cores with 256 GB of RAM using SQL as a dodgy data warehouse.

I don't know if it makes any difference but the HBAs are in the x4 expansion slots in the 785's. Our server ops manager says they can handle the performance and by what I have read, x4 Unencoded Data Rate is 16 Gbps (2 GB/sec). Thats 10 times what I am seeing with 180 MB/Sec.

Coming from a Solaris/Oracle and Non Stop with Non Stop SQL backgrounds that easily pushed past this 200 MB/Sec, is there something that is not right with the setup with the HBA's and the onboard 785 slots? A HP person that we raised this with was very vague but said from the quickspecs:

"Througput: 4 Gpbs FC increased aggregate throughput to 800 MBps per channel in full-duplex mode." So, 1.6 GB/s is all we say the dual port will do.

Thats still well above what we need.

The HBAs (FC1142SR) are Qlogic and the scli software says something that bothers me.

...
Actual Data Rate: 4 Gpbs
...
PCIe Max Bus Width: x4
PCIe Max Bus Speed: 2.5 Gpbs
PCIe Negotiated Width: x4
PCIe Negotiated Speed: 2.5 Gbps

Thats got to be some sort of clue but no one wants to talk about it anymore.

Stephen