CIFS is slower on CentOS 7.1 than on Centos 6.7. What is the reason?

Question

linux

Installed two clean systems on ESXi.
Accordingly - CentOS 7.1 and CentOS 6.7
The same network resource under Windows is mounted on both machines using CIFS.
Essence of the question:
When copying a file from Windows balls to CentOS 7.1 - the speed is about 20Mb / s.
When copying the same file from Windows shares to CentOS 6.7 - the speed is about 100Mb / s.
When comparing command output cat /proc/mountsbetween 7.1 and 6.7, the difference is only in the cache parameter.
On 7.1 - cache = strict
On 6.7 - cache = loose
If you remount on a 7.1 share with the cache=loose parameter - the copy speed increases to 40 - 50 Mb / s - but not up to 100Mb / s.
Perhaps someone has come across such a nuance? What could be the reason?

Answer 1

1. Check your tcp/ip settings
2. Check which disk drivers are installed
3. vmware tools installed on the new vm-ku? Do they support 7.1?

Answer 2

1. What exactly? I don't quite understand the question.
2. Direct-Access VMware Virtual disk - on both machines
3. Both machines have open-vm-tools