Poor file copy speed from VMware Guests
Posted on 2014-11-14
We have a VMware Vsphere system running on HP Proliant servers, and are having trouble with slow file copy speeds across the Cisco 3850 switch they're connected to. We have had many people look at this and it's still eluding everyone to the point we're desperate now for the breakthrough resolution! We've had Cisco check the Catalyst 3850 switch, HP check the Proliant DL360 G4p servers, and are now having VMware look at the ESX 5.1 VSphere system for the 2nd or 3rd time now, in 2 months. Every time we think we've found the problem - doesn't fix it. So now we're trying to appeal to the open Experts forum here to see if anyone has anything new to suggest. We've checked many things, and don't have enough space to list everything here, but maybe somebody will think of something we haven't yet. What we're using to gauge the performance is a variety of things. One is a LAN Speedtest utility that builds a 50MB file in memory and transfers it from the source machine to a destination UNC location, and measures throughput. We also have been using IPERF, as well as doing a simple file copy operation from one VM to another, and watching the MB/s ratio. Here's the latest results from those tests, from just this morning:
DETAILS ON GUESTS USED IN TESTING:
“LACOTS3” VM – Host 192.168.1.17, datastore VNX_DS_1
“LACOFRX” VM – Host 192.168.1.17, datastore VNX_DS_2
“LACOAXT” VM – Host 192.168.1.28, datastore VNX_DS_1
2 VM GUESTS ON SAME HOST (LACOTS3 TO LACOFRX)
• 900M file copy: ~70MB/s
• LAN_Speedtest: 50M file resulted in WR speed of 224Mbps / READ speed of 339Mbps
• IPERF: 10 sec test, 12.6M copied at 10.4 Mbps
2 VM GUESTS ACROSS 2 HOSTS (LACOTS3 TO LACOAXT)
• 900M file copy: ~16MB/s
• LAN_Speedtest: 50M file resulted in WR speed of 304Mbps / READ speed of 196Mbps
• IPERF: 10 sec test, 152M copied at 127 Mbps
One thing that seems strange, is there's an inverse relationship between the IPERF results, and the file copy ratio.
If anyone has any ideas of what could be causing the poor performance, we're all ears. I realize that you may need more information before making a suggestion, and I'm ready to clarify more.
Thanks for your help.