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NinoFarina
3 Posts
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October 16th, 2013 15:00
Data transfer rate slows when adding third 6224 to the stack
Hi All,
We are running 20 devices, each with a 1Gb connection, through a PowerConnect 6224. We stack 2 of these switches using the 12Gb stacking cable, and then connect one switch to a HP Z820 workstation via a 10Gbe card and a CX4 cable.
Running 2 switches in the stack gives us a data rate per device of 7MB per second. This is the max speed from a single device due to USB/SSD limitations.
Let's do this in bits per second.
20 devices all downloading at once is 1.12Gb/sec
2 switches of devices is 2.24Gb/sec
3 switches of devices is 3.36Gb/sec
When we look at our data rate for 1 and 2 switches worth of devices we get 57Mb/sec per device
When we look at our data rate for 1 and 2 and 3 switches worth of devices we get 40Mb/sec per device
We have tried increasing the MTU but that makes things worse. There may be a magic number we have missed.
Does anyone have any ideas?
Thanks in advance.
Nino.
NinoFarina
3 Posts
349
0
Posted October 17th, 2013 13:00
Hi Daniel,
Thanks for your prompt reply. We have done very little troubleshooting on the switches, having only just ruled out spindle speed as an issue by mounting to a SSD rather than a SAS drive.
We are running a slightly older Firmware version so that would be a next step. We are averse to change so when we found a firmware level that did what we needed we stuck with it. Our systems are difficult to upgrade once they are in the field. We will try the latest firmware level next and check log files. So far the logs have shown no transmit / receive errors or dropped packets, but that was a quick look.
It will be some time before we get back to you as another project has just thundered into the room and sat down firmly in the middle of my desk. The system we are testing with will have to be put aside for a few days. Hopefully we will get back to this in less than a week.
Best regards,
Nino.