Created attachment 1144328 [details]
Iozone console logs

Description of problem:

I see a slight regression on random write throughputs on gNFS mounts.

This is from one of the automated runs :

With 3.1.2 (baseline):  mean rand write throughput = 273697.822500 KB/s

With 3.1.3 : mean rand write throughput= 233082.450000 KB/s

Regression : ~ 14.8%

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

glusterfs-3.7.5-19.el6rhs.x86_64

How reproducible:

2/2

Steps to Reproduce:

1. Run iozone random R/W test(I=2) on nfs mounts with 3.1.2 thrice
2. Run same test thrice after upgrading to RHGS 3.1.3
3. The mean throughputs should not vary by more than 10%


Actual results:

Random Writes regressed by >10%


Expected results:

Regression Threshold is 10%


Additional info:


OS : RHEL 6.7

Iozone was used in a distributed multithreaded manner with a 2G file size ,record size of 64K and a total of 16 threads.


Setup consisted of 4 servers,4 clients (1X mount per server) on 10GbE network.

Volume Settings :

[root@gqas001 ~]# gluster v info

 
Volume Name: testvol
Type: Distributed-Replicate
Volume ID: 2a668beb-7f26-48f9-8550-157108fe1a55
Status: Started
Number of Bricks: 2 x 2 = 4
Transport-type: tcp
Bricks:
Brick1: gqas001.sbu.lab.eng.bos.redhat.com:/bricks/testvol_brick0
Brick2: gqas014.sbu.lab.eng.bos.redhat.com:/bricks/testvol_brick1
Brick3: gqas015.sbu.lab.eng.bos.redhat.com:/bricks/testvol_brick2
Brick4: gqas016.sbu.lab.eng.bos.redhat.com:/bricks/testvol_brick3
Options Reconfigured:
performance.readdir-ahead: on
performance.stat-prefetch: off
server.allow-insecure: on
[root@gqas001 ~]# 
[root@gqas001 ~]# 

Console logs attached.