On May 9, 2015, at 2:34 PM, Michael Eager eager@eagerm.com wrote:
I am setting up a file server with CentOS 7. I'm seeing performance which is considerably slower than a similar server running CentOS 6.6. A 3Gb directory can be copied to/from the CentOS 6.6 server in about 50 seconds. The same directory takes about 270 seconds to copy to/from the CentOS 7 system.
I see the same performance difference with NFS mounted file systems or using scp, so it doesn't appear to be an NFS issue. The MTU on the NICs on both systems is 1500, and changing it to 6000 on the CentOS 7 system had no effect.
Anyone have any ideas what might cause this problem or how to fix it?
3GB/50seconds = 480Mbps
Can't speak directly to centos6/7 differences nor NFS on centos6/7....
I've seen NFS(netapp filer to vmware host to windows VM) sustain 10000Mbps. So the NFS protocol itself isn't the bottleneck given sufficient hardware. Since scp performs similar to NFS the on the wire protocol isn't the problem.
Verify the MTU setting: ping a.b.c.d -M do -s 8972 Or in your case: ping a.b.c.d -M do -s 5972 (6000 is a very odd MTU)
I'd start by getting the latest/validated driver from $NICVendor.
What IO throughput does the local file system give? Test with hdparm / dd / iometer / sqlio / cp -a /path /dev/null
Test sever to server with iperf as others suggested.
Hope that points you in the right direction.
Steven Tardy