Description of problem:
From a Windows 7 client, we experienced a huge performance difference between writing to an EC volume and a 3-way replication volume. 

   Windows 7   -> EC(4+2)volume     ：22MB/sec
   Windows 7   -> 3-Way replication ：90MB/sec

The test method is to copy a 20Gb file to the volume.
And the copy speed is from the copy window in Windows OS.

Version-Release number of selected component (if applicable):
RHGS 3.2

How reproducible:
Every time

Steps to Reproduce:
1. access to an EC volume and a 3-way replicate volume in a windows 7 client
2. copy a big file into EC volume shared directory
3. copy a big file into replicate volume shared directory

Actual results:
Copy to EC volume will cost longer than copy to 3-way replication volume

Expected results:
The copy time should be almost the same.

Additional info:
We also checked this write performance issue from a windows 2012 client, and with no performance difference occurred.

   Windows Server 2012 -> EC(4+2)volume     ：100MB/sec
   Windows Server 2012 -> 3-Way replication ：100MB/sec